I had a very severe reaction to a chemo drug 4 weeks ago that sounds similar.

My hands, arms, feet, and legs turned an angry purple red, numb, burning, stinging, swilled beyond belief. I had to have my rings cut off. Then it all turned bright red and blistered under the skin. Started to peel, still is.

Extremely painful, 5 days of steroids and that was it. Med onc called it hand foot syndrome, but it went way beyond that.

Chemo has been stopped until after surgery, he doesn't want me to have more. Depends if the surgeon gets all the cancer.

So yes, I fully understand this pain. I hope neither of us ever get it again.