Anyone ever deal with a horse that gets a shoe boil? Its my first time dealing with it. Took him to the vet yesterday and was told to get one of those donut things. . and couldn't drain it. :( 

Super bummed. . because of course, this is my 3 year old that I'm hoping to sell soon. I hope it will go down. 

Any positive experiences will be greatly appreciated. 

Poultice , dmso or anything to help draw the swelling. Don't drain it. 

You can use some of the old style Professionals Choice bell boots that are thick. Put 1 or 2 on the foot to protect his elbow.
Horses with chronically sore hocks will sometimes get shoeboils. Sometimes their shoe is too long and pokes them, sometimes there are some sharp pieces of their foot that poke the elbow that you can file off to prevent this happening again. If he is shod, make sure the shoer bevels the edges of the heels of the shoe and makes heel checks..

if you can figure out the cause and get the shoeboil heeled up you can usually prevent it from happening again, otherwise , you will have a chronic problem that is a bugger to manage.