My screen is dimming when lots of pixels are dark, how do I fix it?

My screen is dimming when lots of pixels are dark, how do I fix it?

The screen on my TI-83 keeps becoming dim when I rapidly type numbers, or go into certain things like the finance app. I think it's because there are too many pixels that are black that it seems to refuse to show up. Is there a way to fix it without opening it up, or do I have to order a replacement screen?