It is really hard to see the details in the pictures. From what I can see & what you are describing it could be a few different things.
It could be some scar tissue or an irritation from where the clamps were. Or it could be scar tissue/irratation from the sutures IF the sutures were off to the side a little. Some vets & doctors do sutures differently. It could also just be an irratation from the the supplies they used, latex, disinfectants, etc....
Did she lick the area at all? Maybe that caused it?

It might not be related to the spaying either, it could just be an irration she developed from something else.

It could also be a cyst???

I don't know if they happened to have sutures there, or the clamps punctured her skin or the like or what but one of my own surgeries that I had, they had accidently sutured wrong or closed me up wrong, they did something wrong, but I have these 2 pimple like things that come & go, they think a hair folicle or two was distrupted which sometimes causes an ingrown hair or a pimple.

I'd say as long as it doesn't get worse I'd just keep an eye on it. If it doesn't go away within a couple weeks I'd take her back to have it looked at again, maybe aspirated to see exactly what it is.