normal levels of b12 may be based on out of date numbers. as far as b12 goes you should be taking it everyday and not depend on a once a month shot to provide you what you need. you are going to have to do some research here on some of these topics to understand all that is being discussed. as im sure you have deduced, since your pn resulted from vitamin deficiencies due to your bariatric surgery and even with treatment with vitamins since then your symptoms continue you need more than what you are getting now or vitamins that are not being supplied to you.

actually most people have large fiber neuropathy who have PN. It is what shows up on an emg though it may not show up until enough damage has been done. i have large fiber pn with axonal involvement affecting the sensory nerves and to a lesser extent the motor nerves. The myelin sheath around the large fiber nerves are also being affected because of the degeneration of the axon. some people with large fiber only have axonal involvement or demyelination of the myelin sheath. there are also people with mixed large and small fiber neuropathy.