I also can't back this up, but it may be possible... you say that she's trying to get something out of her mouth it seems. For anyone who's seen the inside of a chins mouth they can see how the check pouches work, it's kind like of like it's split into two sections. The front section is the front incisors which are used to bite food, then you have the cheek pouches which pretty much come in toward the center of the mouth and sort of section off the mouth, then the molars in the back section. With all of the skin in there I can see that it would be easy to get food stuck in there and if their tongue is not agile enough they may get something stuck in there to get out, using their paws, just one or two swipes may help get it unstuck and moved forward. I mean, I'm ended up with half my hand in my mouth to get out something lodged between the back of my check and my teeth.
Dawn if your vet's fancy new equipment includes a video scope that would be awesome to get pictures if you ever get the chance. Also like Dawn said it can be a symptom of dental issues, the swiping would be often and more often when eating, think of it like someone rubbing something that's sore to try to make it feel better.
Whiskers are used for perception and they also apparently serve a purpose of distinction. It is not unusual for a dominant chin to chew off the whiskers of a chin who's lower on the pole so to say, so perhaps in some aspect it's a sign of arrogance or saying look at me, no one's chewed my whiskers, as well as keeping them clean?