I believe they insert an instrument vaginally in order to raise the uterus to give them more room to manuever during the procedure.
I did read that they sometimes have to insert something in that area? I am not sure what and can't remember why. Oh, it was something to move the uterus if it is in the way? Read more on it, but I would start by calling if it is that bad. Hope you feel better!
My concern is that with laparotomy, they are working from the exterior/abdominal area, not via vaginal entry. So why would that area be swollen?
I actually experienced this with 2 out of 3 of my surgeries. My doctor(s) said it was completely normal to bruise/swell because they were in there doing a lot. Neither of them seemed to be worried though I clearly was (each time). And...the bruising and swelling went away completely in about 2 weeks. But if you're still unsure, or notice that its not getting better...you could always call and make sure.
I would be calling the surgeon's office regarding this. That is not a traditional side effect of a laparotomy.