Why does my phone work but I have a blank screen?

[AC Question]

Help! Blank screen

I dropped my phone, everything works perfectly fine. I can even play music but the screen is blank. No cracks, no green lines, my phone has been opened up before, I cracked my glass screen, and got it fixed.
it's been a month, but I still haven't returned to the store to get the warranty plastic thing they put inside my phone removed, so the screen is kinda sticking out a bit. Is my motherboard loose or something? Or is it my LCD? I cannot afford an LCD replacement, anything you think might help, please say so.

 

[B. Diddy]

Re: Help! Blank screen

Welcome to Android Central! Just because there is no visible external damage doesn't mean some internal component isn't damaged. This is pretty common--the screen can get damaged relatively easily with a drop. Perhaps there could be a loose connection, but you'd have to open the phone up to check.