There are a few ways to debug this. First, a blank screen is good. That means bspwm is running.
I would confirm that you're xinitrc looks something like
sxhkd &
exec bspwm
The ampersand is important. Next, try spawning a terminal in your xinitrc to see if its getting positioned properly. It should appear somewhat "centered" on the screen. To do this, use this .xinitrc:
sxhkd &