Scratches under the iPhone glass

Hello

Thought I'd post here as I have noticed a couple of scratches have appeared on my iPhone, they are only slight, but I have no idea how they occured and they are noticeable.

The reason I've posted is that they are under the glass, with no visible marks or damage whatsoever to any other part of the phone. The scratches are right at the edge of the glass at the bottom of the phone below the home button. It's almost as if some internal component has scratched at the back of the glass and removed the black coating.

I doubt I can take the phone back, I've had it 3 weeks and the scratches are only small, but I'm a bit disappointed now that for the remainder of my 18 month contract, I will have a less than perfect phone through no fault of my own as far as I can tell.

Does anyone have any ideas how these marks might have appeared? Has anyone else had this happen? I want to make sure I avoid it getting any worse...