Throat swollen during shed?

I noticed in the last few days of Connor's latest shed that the underside of his throat seemed a little swollen. He also was not flicking his tongue at all when I first held him, and Connor is usually a non-stop 'flicker', although the tongue came out after about 20 seconds I suppose. Now, I know that the neck will sometimes swell during the shed cycle (and I'm assuming the tongue business was due to his throat feeling a little uncomfortable) so I'm not terrible worried, but I'm curious as to why this happens and what causes the swelling?

From what I've read, the fluids that they produce to help remove the skin builds up almost like lymph fluid does. I think it shows more at the head and neck areas because those are areas with constricted portions such as where the jaw ties into the skull and where the neck bends.