Swelling is not uncommon after neuter surgery and your vet certainly should have warned you about that. It is usually gone within 2-3 weeks.
What I have been told is that testosterone levels actually can peak after surgery, so a dog that was normally well-behaved can start jumping, mounting etc. We see this infrequently, but it does happen. Testosterone levels slowly go down and level off in 3-4 weeks. Hang in there, and you should see improvement in your dog's behavior!