I, personally, would not call animal control right away, that's sort of a mean thing to do. Keep in mind that your cat spends most of his time inside and so just wandered into another cats territory, I wouldn't be surprised if the neighbors cats got some nasty scratches and bites from your cat as well (Cats like to hide these, so "the cats didn't look hurt" isn't really a sign that the cats aren't actually hurt). Cats fight all the time, it's sort of a normal thing and it's not a good thing but it's very, very common.
The way to avoid cat fights is to keep either your cat or the neighbors cat inside, by the sounds of it you already keep your cat inside so the problems already sort of been solved. You would only really need to call animal control if your cat was constantly being attacked and you or your neighbor couldn't make an agreement on whose cat should stay inside or not. If you want, and you know the neighbor who owns the cat, you can tell the neighbor about the incident and ask for some help paying the vet bill (definitely take your cat to the vet, no question, cat fight wounds can get really infected really quick!), but keep in mind he has no legal obligation to do so.
So I wouldn't call animal control if I were you.