What Causes Puss Filled Lumps In Pubic Area?

Hi I'm female, 17 years old , i weight 13 stone and i am 5'6 and dont have much of a medical history. i suffer from no allegies and have never had any serious illnesses. I have these sort of spot/lumps on my pubic area which when popped pus comes out and then lots of blood, they continue to come back, i have no sexually transmitted diseases and never have had any. I'm a very clean person and was just wondering what they could be :S