Hi Meekos Mommy, I had Bulldozer neutered 5 months ago, when he was 7 months old, and he didn't have any swelling or redness, at all, he didn't even have any pink colour, not even in his stitches area. I would definitely have the vet take a look, just to be on the safe side, especially because if he's on pain meds, he probably isn't feeling any pain, but it still could be an infection or an allergic reaction to the stitches or the surgery. Poor little guy, hope it's nothing serious and just swelling and it goes down. Good luck at the vets tomorrow, and keep us posted on what he says. Feel better Meeko