So I had sex recently unprotected and started noticing a little red mark on my penis head on the side of it. It doesn't itch or burn. I though it felt like a little burn sometimes, but I think it's just because I was thinking about it so much. I did was my penis after sex and dried it with a towel but I don't see how that would cause irritation.. Especially if I don't feel any pain associated with it.. If you have any advice please let me know.