What Causes Cyst Like Growth In The Groin Area?

I always seem to get cyst type things in my groin area, have been to the doctor and dermatologist and no one seems to know what they are or what causes them. I get them the same time of month every month and they last several weeks. I have had one drained, been put on antibiotic courses, birth control and have also been tested for MRSA. The dermatologist wants to put me on acutane which I'm not keen on. There has to be more tests that can be done.