I would definitely see a wound care specialist.....my foster, Summer, was treated at Texas A&M in the soft tissue surgery department. That is the department that deals with wound care.
If you have a vet school close to you, that might be a good place to start! I do think that your pup will more than likely need to be anesthetized so that they can get a really good look at what is going on inside this wound.
Hope this helps.
