There has been a small rash on the shaft of my penis for several months. It is about the size of the area of a pencil eraser. After any sort of rubbing or friction it gets bright red. It does not hurt in any way and the only way i know it's there is because i can see it. I have been tested for other STDs and it is not herpes or syphilis. The skin has never broken on the rash and it doesn't release any fluids. I have had oral sex performed on me and mutual masturbation. What are the risks of transmitting HIV through this rash?