What are these painful nodule like bumps on my vagina with a small pus enclosed sac and become big ?

hi i have had 4 sexual partners ..unproteced sex at times...i am 30 yrs old .. .i recently noticed painful nodule like bumps on my vagina...intially they start out like small pimples with a small pus enclosed sac and eventually they become bigger and very red and bleed out and are very painful..i used to get my hair waxed and now i shave with razor and get laser hair removal on my vagina....i went to the gyno..all test cam back negative (HIV, HERPES , SYPHILIS , gonorhea and clymadia)..she said they dont look like herpes either, but they are very painful and i have noticed more and more of these painful pimples/nodules and they are getting larger and more painful...what else can they be?