Seborhea is a common condition that happens at all stages of life, from infants' cradle cap to old age. There is no reason for you be concerned about HIV (unless you're ill in other ways.) If there's otherwise no reason to be concerned about HIV, having seborrhea is of no relevance that way.
Over-the-counter dandruff shampoos containing zinc or tar are helpful. If you need more help, a dermatologist can prescribe stronger shampoos and topical solutions.
Best.
Dr. Rockoff
Forgot to add Doc,
Its behind one ear.