Quote from the Amazon product discussion threads (not my post--maybe it's someone from here?):
I have had two Kindle Paperwhites with blotches of discoloration on the screen, and I am awaiting a third one tomorrow. Amazon Kindle support is great. They are working with me until this problem is completely resolved. She said it is a hardware defect and informed me that all the Paperwhites with this screen issue should be returned for a replacement. I advise you to contact Amazon Kindle support (2nd level) and explain your screen issues. They will send you out a replacement.
I am getting another one sent overnight - I just hope its a good one with a uniformly white screen and no blotches of color!
Just wanted to give a heads up on this issue.
P.S. Amazon just phoned me and said that their engineers are looking into this matter and wanted more information from me. They want to track all the devices that have this screen issue. If you have any problem with screen discoloration or blotches, please contact Kindle support and inform them as they are sending return labels with special tracking so the engineers can look at these defective devices.
Can't speak to the legitimacy of this, but if anyone else is told something similar, please let us know. This is the kind of action I'm hoping for on Amazon's behalf.