First time poster here...
So I found this thread after having this issue for awhile. It was annoying the hell out of me and and I wound up trying to scratch the lens more to test what could make it scratch. To my surprise it started to clear up! It's a film on the plastic/glass. The earlier poster who said to clean it with toothpaste and a toothbrush was onto something. I believe that they left a film for protection (whether it's UV or something of that nature) on and it's scratching off. Trust me and try this. I was astonished. The scratching was also happening to the little camera as well. This phone has never left a case from day one. I'm positive it's a coating. Now if it's necessary is another story. But my pics are wayyy clearer again.