Bee's Boil

Bee has a Boil on his left elbow. It's gross and looks like a large golf ball.
A boil is often caused from the horse shoe hitting the elbow as the horse attempts to get up after laying down.
The elbow becomes inflamed and swollen.
Bee's Boil came to life over a week ago. I tried a combination of hot and cold compresses, along with bute (aspirin for horses). I also put a doughnut (round rubber device) around his fetlock to protect him should he decide to roll in the dust again. Finally after 4 days I called the vet, Dr. Kerr. He poked a needle in to the affected area and a stream of yellowish serum flowed out. He warned me that it might pop up again. And it did. I eagerly await yet another vet appt. Ugh. The Boil saga continues.....