HI - did you ever figure this out? The same thing just all of a sudden started happening to my daughter. When it started, everything was the same so we could rule out all soaps, shampoos, water, etc. She moved to another country and it stayed the same. It really breaks my heart to see her suffer in agony for about 30 minutes after a shower. She has tried not using a towel, using a hair-dryer to dry herself, everything. How are you doing now>