Dim Screen After Proximity Sensor Replacement?

So, I changed the proximity sensor on my iphone 4 (at&t) and it seemed to go well. However, once I got everything back into place I found that my screen was dim (back light only), very frustrating. Here are the symptoms:

1. It seems everything is still working although I can not see the screen (i.e. can still make calls using voice commands, can hear incoming calls although can not accept since I can not control the screen)

2. I've tested two other screens and neither of them worked. However, the two other screens flash bright white when activated.

3. When replacing the power button bracket I found I had to leave the two screws unscrewed by about a full rotation to allow the power button to "click"

I've tried a hard reset, no dice. I'm letting the battery fully drain as we speak.

Any suggestions on what the problem may be?

Thanks a lot for your help