Why is my screen all whited out?

I recently found my old Gameboy Advance SP in a drawer in my room, and opened it up to play it only to realize that the screen is severely whited out. I vaguely remember possibly dropping it as a kid so that may have been the cause, though I am unsure of that part. All I know is that it makes it nearly impossible to play. Does anyone know what may be the cause of this, or is the device just broken? Is there a simple fix or do I need to replace the whole screen? Thanks in advance for your help! :)