She needs to talk to the pharmacist and not try to adjust her dose by herself.Fentanyl is the strongest opiate known and can take a week or two to get used to.I would suggest taking the
benadryl and putting the patch on a fatty area rather then the arm.Definately phone the pharmacist first because I don't think the patch goes any lower than 25 mcg.Good luck and let us know how she makes out...Dave