So, I dropped my second hand iphone from a good 3 or so feet onto the very hard tiles of my bathroom floor. Now the bottom section of the touchscreen does not work, while the top half does. So I can use the slider to power the phone off, but can't use the slider to unlock my phone.

The glass itself is fine but there is a section on blue "pixelation" in the upper corner of the non functioning touch screen.

What part do I have to get replaced to fix this?