Mariemac, get her in to see her doc and have it checked out. Swollen and distended could result from a number of causes including infection. So please make sure she gets checked out.
I have the exact same problem But mine was from what my surgeon said was gas used to inflate your insides to do an Operation, I was told this would go back down after a couple of days, Its been over a year and I get asked if Im pregnant (Im a guy).