You need to check with a doctor, since if it is from bacterial infection, you'll need antibiotics. Check with the doctor, and check it soon.
Can you have a Dermatologist look at it? You can also have a doctor look at it to see what he/she thinks it is. Don't be embarrassed to tell the doctor about the sex and about he/she looking at it. That's what they are there for. Sorry I'm no help, but I haven't a clue what it is either.