You need to give it time, as I said your body went though a lot and it will react to that.
I've haven't had this surgery, but I've had more then I care to list and they all will cause the body to react in its own way to heal. If you find out down the road that it isn't as flat as you would like it to be a revision surgery could not be down right away. That being said, I believe in time you will see the swelling go down.
Good luck!
Bob