Hello all, I am a 23 year old Caucasian male and recently noticed there was a red mark going horizontal on my stomach and a little much small one on a different part of my stomach. They dont hurt or anything and I cant recall doing anything that could of caused it. I went to the doctor a month back for a sinus infection and he prescribed z-pak, I took the full dose but the infection came back. Maybe that info can help some. Here is a link to an image that I took of the mark.