I would wait and see how good the dust works, make him a dusting area with peat moss,wood ashed if ya can and a bit of clean sand, this will help him remove them naturally, you can add a bit of seven dust to the mixture also won't hurt him, most likely the pen he was kept in had no fresh dusting area with the mites being on hi like they are.I am afraid of that. My thought was that since he used the spray, maybe it didn't get to the skin. When I spoke to my vet he said that Ivermectin wouldn't work on biting lice very well, just sucking lice. I did spray him with permethrin and put Sevin dust in his bedding. Do you think I should treat with ivermectin too?
He will think he is heaven