Crankin, good luck with this -- it sounds horrible.

I don't know if it is anything like the saddle sores I get, but I have one particular place in the "t'aint" area on the left that has twice developed a saddle sore that eventually took me to the dermatologist's for a cortisone injection. But they come up more slowly, fill with blood over and over (yes, I confess to poking a sterilized needle in and squeezing them), and cause excruciating discomfort on the bike. The cortisone shot nips it immediately.

Yours sounds almost like a bacterial infection, a true boil. glad you're getting it checked out, and let us know the results.