Anonymous wrote:OP here: this is a new thing. He does have some skin allergies, but this is a localized thing to one spot on his leg. It may be worth trying some Benadryl though, that's a good idea. We think part of it is that it itches as it is healing.
My dog did this for awhile.
I washed it with plain water a couple of times a day, then dried and put Cortisone cream on it. I did this just before walks or playing, so that she couldn't lick the cream off immediately after it was applied. I also kept her with me in the same room (used baby gates) so that I could keep an eye on her and stop her from licking when feasible.
I gave her a half-dose of Benadryl in the AM, and a full dose in the PM, which not only helped the itching/reactivity but helped her to sleep (cannot lick when sleeping).
What food is your dog on? If it is a mainstream brand (Purina, Alpo, etc.) which contains corn, soy, wheat or other allergens, those could be the culprit.