My monitor isn't showing a picture properly. I

I'm assuming you already tried the brightness adjustment.

From your description, the LCD screen itself seems to be intact. The problem seems to be backlighting which could very well have been damaged by a perimeter impact.

If it's still under warranty, contact the manufacturer. Tell them it just stopped working. Don't elaborate on the details.

If not, find an accredited computer repair shop. It's not a big deal to fix as long as the fix is performed by a trained professional.

Sorry, I wish there was a magic button to push.

Best regards,
Mike