Apply a liberal amount to some gauze, cover the boil, and leave it overnight. The next morning the boil should have drained completely, or close to it! Cleared mine up in two days. It even helps with the pain! You may have to do this for a couple night, but it’s really worth ...
I have found that applying 'blistex' lip cream to the affected area and covering with a band aid/sticky plaster (if you can!) really helps 'bring things to a head' so to speak. Had various and dangerous medications prescribed but nothing has worked to prevent. Sadly, now way past teenag...