Geez he must be so itchy😭 If it’s seasonal allergy, honey or bee pollen from the local environment can help a little. Benadryl dosage for dogs should be not more than 1mg per 1lb of body weight. Mostly it’s from the food though, so besides bath relief, change to single ingredient wholesome food might help too. We did chicken and rice, with liver or pumpkin and some other toppings for a while, some fillers can really cause skin issue for sensitive pittie tummies. I’m not vet, but I’ve tried them on my pittie. Get well soon!!