Hi , 4 weeks ago i had a small hardened lump on my buttocks just below the waist line. After two weeks it increased in size n started paining and pus was formed. I drained out the puss forcefully and took antibiotics for 3 days on doctors prescription . for last two days it has again hardened and its painful again. would you please suggest me what needs to be done. and why is it recurring again and again.