Hi Equine Dentist,
I am on the CRPS forum. I had a nerve injury and repair to my left ankle and am quite familiar with entrapment syndromes.

I can't get on board with severe facial numbness like you are writing about being normal. You said this was new. Did this get worse after the injection?

From the outside that sounds like nerve impingement more than SFN. Could be from any number of things, even swelling from extra fluid in the area from injection. What does you doctor say about it?