I'm 16, and for around 5 months now I've had a blotchy red rash on the underside of my penis. The rash appears in a sort of line, down the middle of the underside, from top to bottom. I always feel an irritation and often an itchiness. The rash feels more smooth than the rest of my penis. I've never had sex before or any sexual contact so an STD is out of the question.
Please could someone give advice!