The only risks for HIV in adults are:
1) Having unprotected (no condom) penetrative anal or vaginal sex, OR
2) Sharing IV drug equipment with other IV drug users.
No one has EVER been infected from receiving oral sex, even if some sites list it as a theoretical risk. If you don't do any of the activities I listed above, you will never have to worry about getting HIV.
Your hives sound like an allergy. An itchy rash isn't a symptom of HIV, and in any case, you had NO RISK for HIV. You should see a doctor about your medical issues if you are concerned, but they have nothing to do with HIV.