In the past couple of weeks I have noticed a small white round circle on the head of my penis. It doesn't burn, itch, or hurt nor does it produce pus. Simply put, it is just there. I'm worried that this may be an STD but I have had recent blood work [negative on everything] and have not been sexually active in the last 5 months. So Maybe it is just a scar? It really bothers me and I'm kind of embarrassed by it. What can I do and will it go away?