I'm pretty sure I've read this before and know the answer, but this is the first time it's happened to me. I waxed a coworkers brows and upper lip, she said she'd gotten blisters when the previous esty waxed so I made sure the wax wasn't too hot and zip zip zipped. 10 minutes after wax she had little blisters coming up on her brows and 5 min after that on her upper lip. I was so disappointed, of course thinking that I wouldn't create the blisters :-) Is this a histamine response to waxing? If so, should she take a benedryl before waxing? Thanks!!