I get a cluster of very itchy blisters on the side of my tailbone every few months. They itch, rupture, clear liquid drains, the area looks like raw hamburger for a few days, then it scabs, falls off, leaving a dark area and then completely clearing up. The whole cycle takes about a month. I've been having this problem for about 15 years after I got a shot on my rump. The cluster started right where I got the shot on my right butt cheek and has slowly moved to the side of my tailbone. The only thing that seems to cut down the cycle in half is dabbing it with vodka. Strange, I know. Can anyone tell me what this is?