If you can shave the hair from the affected area, it will help. Shave the area, and about an inch or less around it. If it is scabby, clean it several times a day, and keep it dry.
If the dog just won’t leave it alone, you should be able to buy an e-collar. Keep it on the dog until the spot clears up.
Benadryl can be given to dogs orally. It has to be just benadryl though. On the back of the box, the only active ingredient should be diphenhydramine HCI.
Dosage is 1 mg per pound (for dogs.) Most tablets come in 25 mg form. For example, a 50 lb dog will need two 25 mg tablets. If the dog weighs less than 25 lbs, you will need to find the liquid form, usually for children. It should come with a little device to measure the amount.
You can also apply small amounts of triple antibiotic ointment to the area.
There are indeed multiple “don’t lick” sprays on the market, but they may further agitate the area.
Try to stay away from anything with alcohol in it.
If you find any fleas, it’s bath time. If there are a lot, you may need to get a good flea prevention. Make sure that it is specifically designed for your dog’s weight.