Most likely it's the film coating only, a common issue on the M8. I used a magic eraser to remove the rest of my scratches and it's clear again. Other common remedies I've seen were rubbing alcohol or toothpaste with Q-tips, corner of a credit card, using a finger nail, and plastic polish. There is a lengthy thread on the issue already, and seems once the film is removed, everyone's pics are fine again. I'm not finding it off hand with the search function (so it's not always your friend), but others will likely chime in here as well.