Suggest Treatment For Irregular Periods And Painful Bumps In Pubic Area

I have very irregular menstrual cycles. Sometimes I don't have one for months, then when I do get it, it can last for 2-3 months. But everytime I do have a cycle, I get this painful bump where the pubic hair is. It hurts so bad that I can barely walk. The bumps always pop and blood and pus comes out. And also a hard core. The bumps occur in the same spot. I don't know what to do.