Hi Eve .....
It sounds like you are doing well post-op. Walking is really the best exercise at this point. You might work on your head imbalance issues by practicing walking down a hallway in your home and moving your head side to side and then up and down while walking ..... increasing the speed of movement as you are able.
As for driving ..... I held off driving for longer than I needed because my rationale was "if I cannot walk straight, how in the world could I drive safely." My husband convinced me to try it in a big, open, empty parking lot. Surprisingly I had no issues driving, it was (and still is for me) only when walking that I experience the imbalance.
In your case, the greater issue is probably one of blurred vision. If you feel sturdy and safe walking, I would think it would be okay to drive. Try it in a safe, uncrowded place and see how you do.
As for facial exercises, I will let others with facial issues give their thoughts .....
Clarice