Problem with iPhone 4S screen discoloration

Hello, I recently replaced the power button flex cable in my iphone.
I managed to fix that issue but now the screen color is distorted/ghosted/burnt in looking.
It looks like the contrast is on 100% all of the time.
Often when I am using an app I can see parts of the keyboard or other apps through the current window.

Here are some photos of the only other case of this issue I have found:
https://discussions.apple.com/thread/4933529

I have checked all the calendar connectors are tight and clean several times and the screen has not been dropped etc.

Thanks,
Chris