The doc probably thought he would be sleeping after he got home and therefore need no more medication is probably the reason they told you to wait so long but honestly,
Glad he is doing better. Believe it or not, in a day or two you won't even know he had any kind of surgery as most dogs are so stoic and rarely show pain unless something like sedation is uninhibiting them. As soon as the anesthetic wears completely off and they've had a good day or two of mostly sleeping and coddling, they act like they are fit as fiddles. I'll bet you are so glad that you've made it through the surgery and that first post-op night with him. The worst is now all over.
__________________  Jeanie and Tibbe One must do the best one can. You may get some marks for a very imperfect answer: you will certainly get none for leaving the question alone. C. S. Lewis |