--it is possible, at a sophisticated center that does skin biopsy, for that sample to be tested for amyloid (mine was out of my original series of skin biopsies at Cornell-Weill/Columbia in NYC--negative, fortunately).

As for further B12 testing, echoes is correct--once you are taking large doses of B12, homocysteine and methylomaic acid (MMA) levels would come down fairly quickly and would not indicate whether you previously had a deficiency. But I would continue taking the B12, based on your response--it has no known toxicity level and the large doses could help depleted body systems repair.