Did your vet recommend putting stuff on it? I would leave it alone. I think the meds only make you feel better and not the horse. It will take time for the granulation tissue to grow back/ fill in. Its problably ichy to him, because of the healing process.
It's hot here so I think Vaseline would melt right off. It's been cold at night though so the flies aren't out so if I can keep him from licking it ill try letting him have it off at night and just keep it covered during the day