Wow! I took my son to dr. to get a culture from doing the same thing, only to get scolded, like I was some child. I should however, be getting the results of the culture back today. This was a dime sized ring though. I started treatment with tea tree as soon as I realized what it was. Yes it was growing, so I too put smashed garlic on it with a bandaid to cover. Burned 30 mins. just like yours. He showered and washed the area and I let him make the decision of whether he wanted to continue this treatment, with the understanding I'd make him wash it off if it got to be too much. He decided to go ahead, and we did. The next morning, like you, there was a blister. We left it uncovered until 8p.m or so, then decided to go and get it tested. That's when the Dr looked at it, (as did several of the residents, and a nurse or two) and looked in my face and said, "That's a burn.Let's not do that again". I didn't answer her but made sure they took a culture before they dressed it and sent him home.I'll post the results when they're in. I'm just so glad to have knowledge to put into practice.
Thanks for sharing.