Bodybuilder - Skin Fold on Abdomen

Hey, I am bodybuilder training for competition several months from now.  I am 175lbs, 10% bodyfat and have never been above 13% bodyfat my entire life.

I have had a skin fold on my lower stomach for about a year now.  It looks like a very deep wrinkle right on top of my abs.  It is very unappealing and is detrimental to my success.  I'm really bothered by it and when people see it when I have my shirt off they are disgusted.

I've done some research and thinking about it myself.  Here's what I think it may be from:

Bad Posture, Sleeping on Stomach, or Fat Gain.

But I am unsure, I would like some professional advice.  I did go from 8% fat to 10% fat when I first noticed it.  Maybe I am just unlucky and have to keep my bodyfat lower to keep this unsightly thing away?

Here is a pic.

http://img519.imageshack.us/img519/1646/fatskinlinect4.jpg