Scratched Camera Lens / Cover

Hey all,

So the back camera lens on my iPhone 5, the unscratched one, appears to have chipped!

See: http://twitpic.com/bmc758

It hasn't suffered a fall and no matter how hard I try I cannot see a mark on the lense from the outside, so it must be tiny OR somethings gone wrong on the inside.

Should I send back to Apple or is there a replacement part I can buy?

This is pretty sad since I'm heading on holiday, one I've planned for years, and so this will make the photos terrible :(

Really hope to sort before Christmas but I'm probable looking for a Miracle.