This is the face she makes when she is going to bite or claw.
It happens when she has been overstimulated, is anxious, or if he ate something she is reacting to.
It is usually followed by the eyes and head rolling back and quick hopping in place, while she claws you and growls through her clenched teeth, “Squeeze me, squeeze me, squeeze me.”
If I catch it straight away I can give her squeezes and hold her to help calm her down if not it takes a while to help her feel calm and relaxed.
I have to be very quick usually, I can catch it before the second phase.