amuk

I assume you have had neck, shoulder, and arm pain (at least) and that playing your horn increased the pain while you were playing.
I also assume that the incision will be on the front of your neck rather than the back since that generally has fewer complications.
You'll have scar tissue based on the skill of the surgeon and any complications that might arise. But you should be all healed up in 5-6 weeks. Get post-surgical physical therapy to help strengthen your muscles in your neck and upper back.
There might be pain in starting playing but that should go away soon---use a light horn not one of those 4 pound monsters.
Basically, it will probably be at least two to three months before you're back to where you were and most of that will just be from the lay-off. But don't rush it.
I haven't had that surgery but I've seen enough disk surgery to make a reasonable guess. I'm a physician by trade.