What Causes Recurring Blister In Between The Vagina And Anus?

I ve had a boil between my vagina and anal for over a year. It swells up and bust then heals and comes back in a week or so. I have a 5 month old now and my ob told me at the beginning of my pregnacy that it was normal during my pregnancy well, i don t believe that because i had it before i was pregnant and still have it. But now for the past week its really huge on the inside, painful and won t pop. I have no insurance and im broke due to just starting a new job after maternity leave. What do i do?