Congrats on his first trip to the Spa!
I have not had the problem you have had with either of our dogs. I am wondering if maybe he forgot what he learned while he was there? Reverted to some old habits?
Our oldest Yorkie was very quiet, and did not bark much at all. But she spent an overnight at the vet's once and came back a barker. A really loud, howling, baying barking Yorkie. It was the most peculiar thing.
I believe she picked up some bad habits while there but was easily corrected to be her old quiet self again. And I am thinking your dog is probably in a similar situation. A few corrections and gentle nudges and he will be back to pre-Spa Jack.
