What causes a red blister on the thigh if HIV is ruled out?

Hi doctor,

Five months ago, I had unprotected sex with a sex worker. I did both oral and vaginal sex. I had done an antibody test (ELISA - enzyme-linked immunosorbent assay) for HIV 1 and HIV 2 in the 13th week after exposure, and the result was nonreactive; the value observed was 0.295. Again, in the 20th week, I had done an antibody test for HIV 1 and HIV 2 which also came nonreactive, and the value was 0.385.

Does this mean that the HIV antibody is building up gradually? I have a red blister or boil (red, non-itchy, no pain, no pus, not like pimples) on my inner thigh. Is this related to HIV? It came in two months after exposure, and till now it has remained there for three months.

Any chance of being positive later? Is my test conclusive? Should I get tested? I am getting married next week, should I need to postpone my marriage?

I am worried about the boil in my inner thigh. Should I need to do a p24 antigen test? I am taking the tablet Finasteride for hair loss and vitamin supplements.

Please help.

Hi doctor,

Thank you for the reply.

I hope that you remember the last time I consulted you. I had unprotected sex with a sex worker around six months back and got tested for an antibody test at 13 weeks and the 20th week, which came back negative. After going through the internet, I found that the long-term use of steroids like Finasteride will damage your immune system.

Now I am really afraid that all my antibody tests came back negative because my body is unable to produce sufficient antibodies against the virus due to a damaged immune system; also, the values at the 20-week test have slightly increased from 0.294 to 0.385.

If that is the case, how long should I wait for the test to be conclusive? What does an impaired system look like? Do you think that long-term usage of Finasteride will delay the production of antibodies? Please kindly address all my concerns.

I am getting married next month. I have been dying of fear for the past six months after the exposure.

Please explain things in detail.