I'm so sorry. Those burns are very, very serious and clearly this treatment was done at way too high a setting and by someone very inexperienced. The underarms should never, ever burn like this and aren't even exposed to the sun like other areas of the body! You need to see a board-certified dermatologist asap for treatment and get some topical ointments to put on to stop the burn and blisters as best you can. Do not pick it, do not exfoliate it, do not pop the blisters. Based on these burns, I'm sorry to say that I would assume you will have some hyper and/or hypo pigmentation problems in the future, but addressing these burns now will help some. Please do not return to the office that did this or have any treatments done there again. This is clearly inexperience and a very, very poor treatment!