pimples? blood boils?

hi everyone, i seem to keep having this same recurring problem that has never happened to me before. a little bit below my vagina but not quite near the anus, on the inner thighs a bit, i keep getting these huge pimples or boils (they have no head) usually where my underwear rubs against. i have never had this problem but now it is happening quite frequently and rubs when i walk making them quite painful. i use compresses and they eventually go away, but then come back. is there anything i can do to prevent these.