Messed up pixels

Over the weekend, a small cluster of pixels in the lower left corner of my phone started acting up. It started as about a 1/4" square section where a bunch of pixels stay lit in a neutral grey color. Then, a horizontal line of pixels lit up. That line has gradually gotten wider over the last day and now extends almost all the way across my screen. I did not drop it or do anything that should cause this. I've done a restore and that did not solve the problem. I'm pretty sure it's fried, but does anyone have any insight into what could have caused this? Any way to fix it other than getting a new screen/phone?