How To Treat Sebaceous Cyst Between Thigh And Pelvic Region?

i had what seemed like a sebaecous cyst in crease btw thigh and pelvic. whiteish puss and almost clear oily stuff came out and it went down but came back. its right where my undies bother it and itches and is tender. now it went away again and i havee a new one on opposite crease. it hurts too what should i do