My dog's allergic reaction won't go away after Benadryl, what now?

Hi and thanks for using Petco Pet Education Center, formerly Petcoach! Sorry to hear about Nova Barton having this problem. You should probably consult with your local veterinarian because we have limits of what we discuss on this forum. Benadryl can certainly be given but you should always contact your vet prior to giving any medicine just to make sure it's under the guidance of a licensed professional that you have a client patient veterinary relationship. Your vet can assist you and may advise an appointment so they can better treat Nova Barton. Sometimes allergies and allergic reactions need drugs stronger than just an antihistamine. Again, I hope she gets better. You and her will feel a lot better once you make the call.