If your shots were cyanocobalamin form, and you have the MTHFR mutation, then there will not be a large improvement expected. Cyano is synthetic and some people cannot methylate due to genetic errors, to the methyl form which the body uses.

Also shots tend to be too far apart to be useful for everyone.

I suggest you start oral 5mg (5000 mcg) of methyl type daily on an empty stomach and see if that helps...it can take 3 months or more.

A DNA test would show if you have this DNA problem. If you do the folic acid in your food will not be methylated to methylfolate either, and that would stall your improvements as well.

You can get the DNA test online at 23andme for $99 if your doctor is not informed about it, and refuses to order it for you.
Several posters here over time have had this test and all of them with PN symptoms showed either heterozygous (one gene missing) or homozygous (both genes missing).