Literary Lark, I get recurrent pimples in 3 areas, the left hairline on the back of my neck, a spot that's located lower left on my butt and exactly where my underwear line is on the front of my left thigh. I don't know why all on the left. We're talking a good 30 years of this! I've been looked at by many doctors, dermatologists, internists, PCP's, you name it and the common consensus is some people get them, some people don't. For me, I strongly believe it has something to do with changes in hair follicles, hormones and sebaceous glands. Friction is a good guess as an instigator. I stopped having my hairline shaved during haircuts because of this. Too much sitting on my duff seems to be a trigger for the pimple/boil on my butt. That one is super painful!

Reducing or eliminating the friction in the affected area is my goal. Maybe a change to hipster underwear instead of bikini might be helpful for you. Close shaving or any change to the hair direction might be something to give some thought to. Good luck!