Change "Follow" & "Unfollow" Text.

yzc_follows_translate_text.php

<?php

/**
 * Change "Follow" & "Unfollow" Text.
 */
function yzc_follows_translate_text( $translated_text ) {
    switch ( $translated_text ) {
        case 'Follow' :
            $translated_text = __( 'New Follow Text', 'youzer' );
            break;        
        case 'Unfollow' :
            $translated_text = __( 'New unFollow Text', 'youzer' );
            break;
    }
    return $translated_text;
}
add_filter( 'gettext_with_context', 'yzc_translate_text', 99999 );