What Causes Painful Red Bumps In Vagina?

I just went to the carribean for spring break and on the last day I noticed small red bumps on my outer vagina where hair grows and a few on the inner side of the labia. The next day these red bumps became super painful and had a yellowy substance (almost like puss). A week before i went on vacation I did have sex with my boyfriend, but he was just tested and came back negative. Could this be herpes or something else such a folliculitis or something from being in the carribean where it s a hot and moist environment.