I was out shooting a month or so ago. I tripped and landed pretty hard but my pack stayed on my back and only got shaken around. I checked to make sure everythign was fine and it seemed so. Last night when i was taking my stuff out for general inspection and cleaning I found that the lens cap to my nikon 24mm had come off. I assume it happened in my slip. Now there are scuff marks in the front element. I assume it is only in the coating.

What effect will this have on the image quality, and can it be repaired?