cat healing after spaying

had both my girls spayed about four days ago. thier behaviour is the same, ive noticed no discharge or discomfort, but i have noticed a firm swelling around the injury sight that doesnt seem to bother them.

Despite my best efforts they have gotten out to frolic about 5 times in the last four days, i know my bigger girl has been scaling roofs! i lock them away but the second i have something to do my dear little four year old lets them out to play! she doesnt understand that the cats need to be inside, after last time i sent her to her room. but even when they are locked away i can hear them jumping around. 

anyway, cats have not been calm, they have not been contained, and they certainly have no interest in changing. should the swelling concern me? any tips on getting these animals to chill out? any signs that i need to watch for if there is an issue?

Firm swelling can be pretty common, especially when the cat has been active. I kept my cat in a bedroom after her spay for a few days, but didn't restrict her much after that either. She kind of self-restricted, and also, I put a onesie on her, which bummed her out a bit. After her spay, she had firm swelling at the incision site a couple of days. It wasn't hot to the touch, no redness, no discharge, but the lump was between the size of a grape and a walnut, and the vet said it was an abnormally-sized lump. So, I ended up getting an ultrasound done for my cat just to be sure, but it ended up being a suture reaction and went away on its own after a week or so. Potential red flags to look for would be redness and hotness at the incision site (which could mean an abscess/infection), the lump getting larger, and overall changes to wellness (like fever, vomiting, lethargy, etc).