perfectly normal. When I got my boys neutered they were a little groggy from the meds for like an hour or so but still acted perfectly normal was hoping to drug them some more to make it easier to keep them still afterwards they were ready to go. Before I get any bad messages I wouldn't just drug my dogs.
Definately, keep activity down to a minimum. Currently, I'm seeing the results of letting my dog have too much access to the backyard while healing. His scrotum is swollen enough to look like he never had the surgery.
Oh my! Call me ignorant, but I was only looking at the incision and not the scrotum. His is still (forgive me) "hanging" there. Should it not be? Good gosh! I too, let him have access to the backyard since he was just laying around on my bed when he was in the house. But he did run around a bit outside. His surgery was Wednesday of last week. Should I "not" see any scrotum at this point? Can you tell this is my first neutered male dog?
It's actually normal for an adult dog to "swell". That is why you need to keep him as quiet as possible. Basically, it's blood pooling in the scrotum and the body will reabsorb it. However, you probably should call your vet. I had a foster that swelled like that and he had an infection. You can ice it as well. I sat for 10 minutes at a time, once every hour, with an ice pack on it for him.