If you have a B12 deficiency presumably it will last forever. But luckily it is probably the cheapest medication that is made. You seem to have mastered the dosage and you will see on a similar post you can only absorb that which you can store. Some doctors give oral B12 but if it can't be absorbed in the stomach in the first place it seems couterproductive to give a pill. Also patches have been said to be good but you know if it is a needle you are truly getting it. Seemingly recent testing techniques are better for detecting levels and the Schilling test may tell you why or where you are not absorbing. But probably academic at best. Your B12 level is 1652, I don't know if that is good, I looked it up and in and it should be 200-900 picograms per millilitre. Two things I do know that are important in B12 and it is that folks past middle age have a regular look at their lower legs and see if the hair is beginning to disapear, I am lead to believe this sign begins before toe tingling or numbness. The other is to give large doses of B12 no matter how many picolitres they test if the person begins to exibit signs of dementia.
James thanks for the insight. My condition is passed all of that as I was dx with subacute combined degeneration of my spine as a result of B12 deficency. I have B12 neuropathy in my feet, legs and groin area and my arms have it down to both hands. It is something that came on at age 55 and it slammed me. Daily it is a chore to move and the simpliest thing is now very difficult. I pray someday to get better. I am hoping to get some answers. Thanks again