My dog wont stop licking his wound and I can't figure out how to stop it?

My dog has allergies also,it took alot of trial and error but finally someone told me about a limited ingredient dry dog food,there's a few I used Venison and sweet potato.It was amazing,(my dog had diareah)the allergy symptoms were gone in 3 days.I gradually added a new food to find out what her allergy is,so far it's chicken,they say it's usually a protein.I'm not sure what to do about your dogs paw,Good luck though!