I am sorry to hear about Betito's tail. This is not unusual; when a dog has a wound on his tail he can become obsessive about chewing on it. I once saw a Labrador who had just a large scratch on the tail, and until we finally got him to leave it alone so it could heal, he has a Rottweiller tail.
Is he getting pain medication? This must be painful from what you describe, and pain will contribute to his wanting to lick and chew his tail.
This will not heal, until we get him to stop licking the tail. If a cone collar is not enough, I would get a Bite Not collar, or a larger cone, so he absolutely cannot get at it, and wear it 24/7. I would start him on pain medication: anti inflammatory, plus gabapentin. I would consider giving him a mild tranquilizer for awhile, such as acepromazine.
If there is dead skin and meat hanging from the tail, that needs to removed. If it is dead, it won't regrow and is just irritating and making him want to bite the tail. I would do a second surgery to remove any dead loose skin and meat, enough to sew up and cover any exposed bone. I would only take what I have to, and try to save as much tail as possible.
Let me know what other questions you have. The sooner you get this treated, the more of his tail will be saved.