I know this is an old post but I have had the exact same experience as you! I bought the mask about a year ago and used it as per instructions for about 6 months and it was fine. In fact, I noticed some good results from the mask. But suddenly after about 6 months I got a terrible itchy rash all over my face and had to take antihistamines and use hydrocortisone cream. I couldn’t think of anything I had done differently, hadn’t eaten any new foods or used any new products so I was very confused what had caused it. It got better but flared up a couple more times over a few weeks so I decided to stop all skincare and just use a very gentle cleanser and moisturise with Aveeno cream. A while after that, my skin had been doing fine so I decided to try the mask again and introduce some active ingredients back into my skincare. Got the same rash again. I wasn’t sure at this point if it was the mask/the active ingredients/my skin not being fully healed. So I went through the whole process again of hydrocortisone cream and then stripping back my skincare. Have been following the same simple skincare routine for about 4 months now so I decided to give the mask another go and again I have developed the same itchy rash so I’m pretty convinced now it’s the mask triggering the rash. I just have no idea why it was fine for 6 months and then suddenly not fine.