Both my cats had the swelling, not sure if they still had it a week after the spay, but they had it for a bit. On my older cat that was spayed about 5 yrs ago, the swelling was all along the incision, but on the younger, there was just a small "bump". My vet says it's just the tissues and whatnot swelling a bit, after all, they've been cut. As long as the skin looks fine, not red or irritated, and there's no oozing or anything, no worries. And my vet has never said anything about being too active, it's just a thing that happens with some cats when they're spayed. The tissues can also become slightly irritated due to the stitches and cause swelling, but again, if it looks fine otherwise, no worries. And the vets have never told me to try and limit the cats from moving, that they'd know how much they can handle. They seemed to, wouldn't jump around at all the first few days, and very cautiously for a while after that. Would say that after about a week they were moving about as normal.