Brain Injury Support Group

I don't know anything about tongue numbness, but your left arm & hand I do have some experience in. I recently had surgergy due to numbness in my left arm and numbness in my left pinkie and ring finger. My ulnar nerve was compressed and needed to be repositioned. (this was from a MVC)If the numbnesss is in your thumb and index finger than it is caused by the radial nerve. My Neurologist gave me an EEG to find out where the nerve disconnect was.
You should ask your doctor, as this shouldn't go untreated. I was told that if I didn't have the surgery, the nerve would eventually get weaker and weaker and some day my left hand would be completely useless. In fact, my left pinkie was already basically paralyzed by the time I had the surgery. Go have it checked out to be on the safe side. Good luck and let us know.