Hi,
It could be fooliculitis or just acne in a less comon area.Folliculitis is inflammation or infection of one or more hair follicles (openings in the skin that enclose hair).It can develop on any part of the body, but is most likely to occur on the scalp, face, or parts of the arms, armpits, or legs not usually covered by clothing.
Scratching the affected area can trap fungus or bacteria under the fingernails and spread the infection to hair follicles on other parts of the body.Never try to pop them as you will only aggravate the condition.
Bacterial folliculitis may disappear without treatment, but is likely to recur. Non-prescription topical antibiotics like Bacitracin, Mycitracin, or Neomycin, gently rubbed on to affected areas three or four times a day, can clear up a small number of bacterial folliculitis pustules.
ref:http://www.myonlinewellness.com/topic/topic100586840
During periods it is common for acne flare-up.This could also be the case. It will resolve by itself as the period is over.
This is not a sexually transmitted disease. You get that only if you have sex with an infected partner.
Are the bumps around hair follicles? Maybe you had a dirty razor when shaving and infected the follicle. look up folliculitis. Don't pop anything!
You force bacteria deeper in the skin. This doesn't like anything serious.
Certainly not anything to worry about.