Tampermonkey userscript to show which of your posts got flagged. Requires you to be logged in on Tumblr and on the dashboard.

tumblr_flagging_score_checker.js

// ==UserScript==
// @name         Tumblr flagging checker
// @namespace    http://tampermonkey.net/
// @version      0.2.3
// @updateURL    https://https://gist.githubusercontent.com/boisei0/2ea7d7145d04a1cc5864d316271d09fd/raw/tumblr_flagging_score_checker.js
// @description  Will test posts and displays the scores for NSFW/explicit content and if they got flagged
// @author       Lena (flight-of-the-felix.tumblr.com)
// @match        https://www.tumblr.com/dashboard
// @grant        GM_xmlhttpRequest
// @grant        GM_addStyle
// @connect      tumblr.com
// ==/UserScript==

(function() {
    'use strict';
    const debug = false;
    const debugFlag = -1;

    let form_key;
    let blogs = {};

    // https://stackoverflow.com/a/47480429
    const delay = ms => new Promise(res => setTimeout(res, ms));

    async function doTumblrXHR(url, options={}) {
        options = Object.assign(options, {url: url, timeout: 15000});
        return await new Promise((resolve, reject) => {
            options.onerror = options.ontimeout = reject;
            options.onload = resolve;

            GM_xmlhttpRequest(options);
        });
    }

    const farmInfo = async () => {
        return new Promise(resolve => {
            document.getElementById('account_button').click();
            return resolve(delay(3000));
        }).then(() => {
            form_key = document.getElementById('tumblr_form_key').getAttribute('content');
            blogs = [...document.querySelectorAll('li.popover_menu_item.popover_menu_item_blog')].map(element => {return {name: element.id.split('--')[1], posts: 0}});
            blogs = blogs.map(blog => {
                let node = document.querySelector(`#blog-list-item--${blog.name} .blog-sub-nav-item-link .blog-sub-nav-item-data`);
                if (node === null) {
                    return blog;
                }
                blog.posts = Number(node.textContent.replace(',', ''))
                return blog;
            });
            if (debug && debugFlag === 1) {
                console.log(blogs);
            }
            return delay(3000);
        }).then(() => {
            document.getElementById('account_button').click();
            return delay(2000);
        });
    }

    function viewBlog(blog_name, limit, offset) {
        if (debug && debugFlag === 2) {
            console.log(`DEBUG: blog: ${blog_name}; limit: ${limit}; offset: ${offset}`);
        }
        let url = `https://www.tumblr.com/svc/indash_blog?tumblelog_name_or_id=${blog_name}&post_id=&limit=${limit}&offset=${offset}&should_bypass_safemode=true&should_bypass_tagfiltering=true`;
        return doTumblrXHR(url, {
            method: 'GET',
            headers: {
                'X-tumblr-form-key': form_key,
                'X-requested-with': 'XMLHttpRequest',
                'Referer': `https://www.tumblr.com/dashboard/blog/${blog_name}`
            },
            responseType: 'json'
        }).then(data => {
            if (data.status === 429) {
                throw Error('Tumblr has decided to rate limit you. Please try again in approximately 1 minute.');
            }

            return data.response.response.posts.map(post => {
                return {
                    type: post.type,
                    is_nsfw: post.is_nsfw,
                    is_nsfw_based_on_score: post.is_nsfw_based_on_score,
                    is_flagged: post.classification === 'explicit',
                    nsfw_score: post.nsfw_score,
                    readable_nsfw_score: `${Math.round(post.nsfw_score * 100 * 10) / 10}%`,
                    post_url: post.post_url,
                    summary: post.summary,
                    post_id: post.id,
                    // No root post checks for now, post.trail is buggy and has been buggy for at least months. Better to just don't until I have a decent fix...
                    // is_root_post: (post.trail.length > 0) ? (post.trail[0].hasOwnProperty('is_root_item') && post.trail[0].hasOwnProperty('is_current_item')) : false,
                    _meta: post // Harder to reach, but who knows...
                }
            });
        }).catch(reason => {
            throw Error(`inside viewBlog; something went wrong: ${reason}`);
        });
    }

    function indexFlags(event) {
        let blog_name = event.target.getAttribute('data-blog_name');
        let outputContainer = document.getElementById('tumblr_flag_output_container');
        outputContainer.innerHTML = '';
        let statusBar = document.getElementById('tumblr_flag_status');
        statusBar.innerHTML = '';

        const totalPosts = blogs.filter(blog => blog.name === blog_name)[0].posts;

        const limit = 10;
        let page = 0;
        let maxPages = Math.floor(totalPosts / limit) + 1;

        if (debug && debugFlag === 3) {
            console.log(`DEBUG: Total posts: ${totalPosts}`);
            console.log(`DEBUG: Total number of requests needed: ${maxPages}`);
        }

        do {
            viewBlog(blog_name, limit, page*limit).then(posts => {
                posts.forEach(post => {
                    if (post.is_flagged) {
                        let postOutputBlock = document.createElement('p');
                        const postLog = `[Flagged] ${post.summary}<br /> *** Post score: ${post.readable_nsfw_score}<br /> *** URL: <a href="${post.post_url}">${post.post_url}</a>`;
                        postOutputBlock.innerHTML = postLog;
                        outputContainer.appendChild(postOutputBlock);
                    }
                });
            }).catch(reason => {
                statusBar.innerHTML = reason;
            });
            page += 1;
        }
        while (page < maxPages);
    }

    farmInfo().then(() => {
        // Set base style needed
        GM_addStyle("#tumblr_flag_container{background-color: #000; color: #fff} #tumblr_flag_container a {color: #fff; font-weight: bold; text-decoration: underline;} #tumblr_flag_container a:link {color: #fff} #tumblr_flag_container a:visited {color: #e9e9e9} #tumblr_flag_container a:hover {color: #e9c4d9} #tumblr_flag_status {color: #ff0000;}");

        // Insert output block
        let outputContainer = document.createElement('div');
        outputContainer.id = 'tumblr_flag_container';
        outputContainer.style.setProperty('display', 'block');
        let t = document.createTextNode('View flag scores for your posts');
        let header = document.createElement('h2');
        header.style.setProperty('font-size', '125%');
        header.appendChild(t);
        t = 'Click on one of your (side)blogs on the right to view all your flagged posts. If there are none, refresh the page, as something went wrong. For a description of the score, see <a href="https://flight-of-the-felix.tumblr.com/post/180788909548/tumblr-and-flagging-an-overview">this long post I wrote earlier</a>.<br />If it fails, ask Tampermonkey if an update is available. If it is the latest version already, message me @ flight-of-the-felix. DM is open for questions.';
        let description = document.createElement('p');
        description.innerHTML = t;

        outputContainer.appendChild(header);
        outputContainer.appendChild(description);

        let statusBar = document.createElement('div');
        statusBar.id = 'tumblr_flag_status';
        statusBar.style.setProperty('width', '100%');
        statusBar.style.setProperty('height', '50px');

        outputContainer.appendChild(statusBar);

        let blogsList = document.createElement('div');
        blogsList.classList.add('tab-bar-container');
        let innerBlogsList = document.createElement('ul');
        innerBlogsList.classList.add('tab_bar', 'tab-bar');
        blogsList.appendChild(innerBlogsList);
        blogsList.style.setProperty('display', 'block');
        blogsList.style.setProperty('overflow-y', 'scroll');
        blogsList.style.setProperty('height', '200px');

        blogs.forEach(blog => {
            let blogItem = document.createElement('li');
            let blogButton = document.createElement('button');
            blogButton.classList.add('tab');
            blogButton.appendChild(document.createTextNode(blog.name));
            blogButton.setAttribute('data-blog_name', blog.name);
            blogButton.addEventListener('click', indexFlags);
            blogItem.appendChild(blogButton);
            innerBlogsList.appendChild(blogItem);
        });
        outputContainer.appendChild(blogsList);

        let innerOutputContainer = document.createElement('div');
        innerOutputContainer.id = 'tumblr_flag_output_container'
        innerOutputContainer.style.setProperty('display', 'block');
        innerOutputContainer.style.setProperty('overflow-y', 'scroll');
        innerOutputContainer.style.setProperty('overflow-wrap', 'break-word');
        innerOutputContainer.style.setProperty('height', '200px');

        outputContainer.appendChild(innerOutputContainer);
        let outputHelper = document.getElementById('posts');
        outputHelper.parentNode.insertBefore(outputContainer, outputHelper);
    });
})();

Change log:
0.2.2: first version with actual updates possible
0.2.3: console.debug replaced by console.log to ease it for Chrome users.