Suggest Treatment For A Pus Filled Bump On The Back

Hi, I have a bump on my back that when I squeeze- discharges this brown cheesy-like puss (for lack of a better word). This discharge has a very foul smell. When I first started squeezing the bump (about a year ago), the puss was whiteish, now its brown. The bump does not have a head, nor is it painful. Please help