Vertical lines on screen

I was trying to set some adhesive on the screen to keep it in place (as the pentalobe screw sockets snapped off), and I followed the guide which said to heat up the phone with a hair dryer until it was too hot to touch. I then turned on the phone and got a temperature warning. After that, the screen went all pixellated, and had vertical lines going down across it with a bluish tint to all colour on the display. I tried a good known screen, and that was fine. Is there any way to fix this, or do I have to replace the screen?