Burning vagina for weeks come and go after protect sex negative std test , what is this ?

HARD TO SAY: This can arise after exposure to a product your skin has a sensitivity to. This could include a spermacide on a condom, the condom, a vaginal wash, etc. would be some possibilities. If so the process would gradually fade if there is no re-exposure and increase if re-exposed. If the agent isn't obvious, having your doc evaluate the history and do an exam is the next step.