I am a married and had a one time unprotected sexual ecounter with an ex-boyfriend 36 days ago. He pulled out pre-ejaculation, but, still it was unprotected. This was the only time I have had sex with anyone other then my spouse. Last week I noticed a rash that is dark and scaley on my neck and back. Both areas are not large rashes, but it seems to be spreading. I read that HIV starts with a rash after 3 weeks, can I really have HIV? I know this was the worse mistake of my life, and the guilt is all ready overwhelming, I don't think I could live with myself if I spread a disease to my husband.