I worked as an X-ray tech for 17 years and have seen plenty of black eyes that did not swell at all, must less swell shut, I even had it happen to me once as a result of a piece of glass being stuck in my temple behind my left eye.
Looks legit to me. It's interesting how perception affects these discussions and our interpretation of events. On the other hand I am more likely to err on the opposite side when viewing things because I think he is a mistake for America. I really don't know if her story is legit or not but I've heard of several instances of aggressive behavior and vandalism, just in my hometown, against McCain supporters who had signs up or bumper stickers.