What Causes Small Pimple Like Bumps In Pelvic Region?

I am 29 yrs old and i had a boyfriend with whom i used to have unprotected sex about 1 yr ago. he has ditched me. prior to having sex with him, i had no other intimate physical relationship with anyone. but i can remember sometimes in my pelvic region there used to be one/two small pimple like small painless bumps rarely. When squeezed, they used to give out yellowish pus and blood and get cured. this has happened 3/4 times in my whole life. I have got one now. Is it serious?