I am 32 and it has been happening to me on and off since I was 16. You are normal. 1 of every 6 women carry a specific Staff infection on their skin. it is usually nothing and does nothing but in some women it can cause a boil or a few boils to appear around the warm moist places on a body. This usually occurs in the area of Vagina, Anus and Armpit. It happens near your period because just before and during a woman's period her core temperature can raise any where from 1/10th of a degree to as high as 1 1/2 of a degree. This is perfect temperature for skin pores to open and hair follicles to open up as well. the bacteria get into the open pore and clog it causing a boil or large pimple. Clean your Pubic area 2x a day or more every day with a anti- bacterial soap (being careful not to wash inside the body) and when the boil occurs clean around it with alcohol before and after you pop it. if you don't pop them be careful that they don't get too big or hard. or that they don't feel "Hot" to the touch that may be a symptom of something a Doctor needs to look at right away.