Hello. Thanks for writing to us at healthcaremagic
Most likely the rashes are due to candida, which is a yeast. It can be acquired sexually. However, it can also start on its own, as you probably also had noticed such rashes before this particular sexual contact.
Itching is usually present and clinically it may appear as a diffuse
redness with moist/macerated bumps.
HIV as such itself is not responsible for causing the rashes. A screening test for HIV at 1 month should be followed by repeat testing at 3 months to cover for the window period of infection. I hope you were told to do follow up after 3 month.
For the rashes, you may try an OTC antifungal e.g
clotrimazole 1% cream, twice daily for a few days.
However, if the rashes don't improve as expected I would suggest that you may visit a
dermatologist for a confirmatory diagnosis.
Regards
Always practice
safe sex with a condom!