Currently Being ModeratedApr 17, 2013 11:11 AM (in response to Csage93)
might be a hardware defect with the proximity sensor.
Try doing a hard reset: Press and hold both the Home button and the Sleep/wake button simultaneously for about 15 seconds and release when the Apple logo appears.
If that doesn't solve the issue, you could also try backing up the device and restoring the device as new.
In that case, follow the steps in: http://support.apple.com/kb/HT4137
NB: set up as a NEW device because a software issue will be in the backup. If the issue persists after restoring as new, you should offer the device for service.
If you're not able to restore the device, this one might help: http://support.apple.com/kb/HT1808
Using his article will erase everything on the device, so make sure you have a backup!
Currently Being ModeratedApr 17, 2013 11:14 AM (in response to Csage93)
Try a reset by pressing the home and sleep buttons until you see the Apple logo, ignoring the slider if, it comes up. Takes about 5-15 secs of button holding and you won't lose any data or settings.
If still an issue, I wouldn't waste any more time on it... just make an appointment at the Genius Bar and get it replaced under warranty.