When I was growing up, Grandma would tape a piece of fatback over a boil and by the next morning the boil would come to a head. I was googling to see if anyone else had ever done this and I ran across several different remedies. I include them for your reading. Good luck.
BOILS - Place a piece of raw potato or a piece of raw fatback (salt bacon) on top of the boil. Wrap with a clean strip of cloth and leave on overnight or longer if needed. Change every day if longer than overnight. This will bring the boil to a head causing it to rupture and heal.