I've had spread to my jaw, teeth, tongue a few times. I needed stellate ganglion blocks to return the areas back to normal. It took months for the pain to ratchet up, but it was also worse than any other area when it got severe, because it was so painful to eat solid food, to talk, and eventually to even breath.

The last block set my neck off, but Epsom Salt Cream REALLY helped with the swelling, and it only took a few days to get back to normal after I tried it. I also awkwardly put Lidocaine patches on my neck too...

A Ketamine Infusion would certainly be worth trying as well.