We had the surgery the same day, and I do have some swelling. I was actually worried that it meant that it was not successful. I want for a follow up today and he told me that my swelling was very normal, and he was not at all concerned by it. He also said not to be surprised if over the next few weeks, they harden up, get some random shooting pains, or swell some more. He also said that one side could experience different things than the other side. It seems like they won't feel normal for at least a couple of months.
So it seems that your hardening is not abnormal, but I recommend giving your PS a call if you have a concern.