Is it normal to get blisters and rash after breast reduction?

I am sorry to hear/see the problem you are experiencing.   I would suggest very close follow-up with your plastic surgeon, who will always be your best resource when it comes to making a clinical diagnosis, treatment recommendations, and/or reassurance. Best wishes.

after any surgery areas around the scar and the scar are very sensitive, I advise you to visit your plastic surgeon to examine you and you can be certain of what actually happens to you. success of surgery depends on the close relationship with your plastic surgeon.