Sadface,
I know very well what you feel

In the acute anxiety we are living under the rule of our alarm system (amygdala) and can not think rationally. That is why we need either informational deprivation, or vacations, or other stress, more strong, to kick existing one out, or just time and patience to calm bloody ringing bell down, or medication and psychological help. Calls for rational thinking never help, no matter if we would ask you to do that or you would try to do it by yourself. Now for you there is not much chance for rational thinking, unfortunately, you are physiologically limited to constant alarm reaction due to pathway in your brain formed becasue of chronic stress and fear, which in turn feeds the fear.
so the only help is a) wait until it would naturally calm down, using, even reluctantly and without passion, any relaxation teqniques you can - breathing, meditation (very hard under hyperactive amygdala), tight daily schedule in terms of sleep, etc., distractive techniques, etc. etc. Good thing is to count from 1 to 10 evey time you want to see your tongue, and even when you allow yourself to do this, just have a look on it without any evaluation, for about a second, next time repeat all this (counting and deep breathing). This may help to break obsessive link; or b) ask for professional psychological and psychiatric help becasue acute anxiety and obsession in BFS is well known and fortunately treatable medical problem, unlike twitching itself. This very solution was helpful for me personally and for many other people.