Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Beware of sudden allergic reaction!

I was reading some of the reactions to Prevage MD and I had exactly the same reaction as another poster. I used it for about a month and suddenly I woke up to a red, burned-feeling face. It itched so badly I cried. Nothing over the counter would stop it. My eyes were swollen shut and then my face began to peel. It was horrible! I ended up going to the doctor and had to have a steroid injection to stop the rapid advancement of my allergic reaction.(Which was progressing even as I sat in the doctor's office.) I do not have overly sensitive skin and have never had a reaction to any lotions or other treatments before, but I made up for lost time when I used Prevage MD. When I told my doctor what had happened she said, "Oh yes, that happens fairly often." That might have been good to know before I shelled out $135. Be very careful. I learned a very expensive lesson.