That's so hard when the symptoms and causes and treatment can all get blurred together. Wow, I didn't realize it could take months to recover from B12 deficiency-related neuropathy. It sounds like you're taking B12 (since I recall that being sublingual?) but just a head's up that excess amounts of B6 can cause neuropathy--I learned that the hard way when trying to supplement my way out of neuropathy (spoiler alert, it didn't work because I don't have a deficiency).

It sounds like a good plan to follow w/ your neurologist and PCP. If the Cymbalta or another medication improves your quality of life, I do think it's worth considering. But if you have concerns about the Cymbalta, you could consider trying gabapentin or Lyrica first, something a little easier to taper down from if need be.

PT might also help give you some strategies for the pain. My PT was able to assess my neuropathy and we did find that some of my burning pain (actually, it was the worst of the burning) was related to disc compression in my spine, which was easily addressed by learning about positional changes and stretches. If only everything were that easy. I've had burning pain in my arms that was referred by disc compression in my neck. I still have neuropathy but getting rid of some of the burning pain still helped a lot. It might be worth looking int.

Wishing you the best of luck.