How Can A Painful Penis Rash With Pus Be Treated?

I have what appears to be a rash on my penis. I have had it for a while and have tried waiting two weeks without sex or masturbation for it to go away. It appears to heal but after either sex or masturbation it comes back. It can be dpainful at times and does excret some pus. It almost appears that I am fearing the skin.