I have been suffering from face numbness for over 6 months. But it isn't actually numb - it just feels numb. And it is not always constant. The moment I think about it, it starts to feel numb. When I am distracted, it goes. It usually correlates with bouts of anxiety. During the time I am feeling anxious, the facial numbness isn't actually present. It is only until afterwards when I have cooled down and recovering that I start to feel the numbness.
It's important to learn your anxiety symptoms so you don't get yourself in vicious circles. I used to do this all the time. When I was anxious about something and then I finally started to clam down, I would then start to experience anxiety symptoms which would make me more anxious again. And this would repeat until I drove myself crazy. So now I can actually keep myself clam despite having tons of symptoms.