My first thought was perhaps the 'swollen tongue' could be related to the side effect of dry mouth. Anxiety can definitely make your face grow numb as well.. This doesn't automatically mean that it's 'all in your head', but hopefully that thought might help you keep from tormenting yourself with the fear of an allergic reaction.

I generally associate allergic reactions with hives and the like. I know with the lamictal I'm taking the troubling signs are swelling, sores, and hives around the mouth.