anesthesia and allergies

My 10 year old 51 pound daughter had her tonsils out yesterday 8-15-06 and now has a rash from her head to her toes, she was under general anesthesia. She is taking Tylenol w/codeine for pain and has had to take it quite alot in the past because she has Complex regional Pain Syndrome, I have called the surgeon and he seems to think it is a reaction to the Tylenol 3 but I am sure it is not, can general anesthesia cause a rash like this? The surgeon said to tke her off of the pain meds but I just can't see letting her be in pain if it is not the Tylenol 3.

Thank You for your help,

Jenn R