Thanks everyone. Mandy is doing ok, but if you don't give her the benadryl, she's right back to itching and chewing on herself. She still has a few more days on the antibiotics and then I will talk to the vet.
Jakesmom, thanks for the advice, but Corinna is right ,no way I want her anymore sedated than she has to be, that's one of the reasons I was afraid to give her the benadryl in the first place.
Mandy says she really appreciates all of the good thoughts and prayers coming her way!