I had unprotected sex exactly two months ago. About two weeks after that I started to get hives. Now instead of hives I get like red marks on my skin. The hives literally itch and burn so bad. Zyrtec helps. The hives/welts/marks come and within minutes they are gone. They appear all over my body including face. This has been happening for two months now. Would hiv rash do this? Could it be herpes? I have been to both my doctor and dermatologist who have both said it is chronic hives. Could it really be chronic hives or does this sound like std? Please help. I'm scared.