Ok so I have this minecraft rig which I downloaded from Shrogg2.
I have added a few of my own simple features but wanted to add things to the facial rig. I have no idea how the facial rig has been made but I have this plane which has stubble on it. I want it to be fixed in one location but follow the deformation of the jaw when it moves.
The controller which is used to move the jaw up and down is already there, I just need to get it to deform this plane. Any help would be great 
Thanks
use a condition node to make sure it only moves when you want it to and link the motion of the control into the condition and the result into the plane when it is attached to the face
for example if the jaw is 0 or less it should not move otherwise you it moves in the units of the jaw, use a multiplydivide to make sure that the movement is as big as you want it to be ( this is the simplest setup i can think of) and if this is too much you can also go with setdrivenkey