Hmm... If I were you, I would remove the hair around his wound. Hair will trap debris, bacteria etc. Use a cone on him - especially at night - you never know when he might be getting at it.
I cannot see the wound properly because of the honey. Would love to see a clear picture with the hair removed. Appears the tissue is very tough, scabbed, and almost necrotic. This is why I asked if you did a biopsy - almost looks like some precancerous lesions that show up in the (human) clinic.
Spray vetericyn on it several times a day. I do not know about the honey so I will not speak to its efficacy. I also like Bag Balm for surface injuries.
Surgery might be a good option. Also get second recommendations from another vet.