About 3-4 weeks ago I had unprotected sex with a person I did not know that well. I seemed to have noticed a small red patch of skin on the underside of my penis that looked somewhat scaly at parts. When I stretch the skin apart, there seems to be a small single cut/crack in the skin. I probably would not have even noticed this if I wasn't concerned with that area. Also, I live in a very hot environment and I tend to sweat a lot in that region throughout the day and when I sleep. There seems to be a slight burn on the patch that has lasted since the incident, however, I am focused on this issue all day so it could just be because I am thinking about it since it comes and goes. Does this seem like an std or just dryness of the skin from sweating? Please help as I am very concerned with this matter.