I would wonder if you had your b12 levels tested after surgery pam? to detect a deficiency?
(were they heading for the basement post surgery?)
anyway, many years ago, I was researching a supplement known as DMSO (they use it here)
and the stuff I saw said that there was a limit, to how big of a molecule DMSO could push through the skin (transdermally)
the limit (going off memory) was around 800 with DMSO
here, we see without DMSO, anything above 500 molecular weight (Dalton) cannot pass through the skin
(500 Dalton rule for skin )
www.ncbi.nlm.nih.gov/pubmed/10839713
now, B12 has a molecular weight of over 1300,
Cyanocobalamin
Chemical Compound
Cyanocobalamin is the most common and widely produced of the chemical compounds that have vitamin activity as vitamin B12. Vitamin B12 is the "generic descriptor" name for any of such vitamers of vitamin B12. Wikipedia
Formula: C63H89CoN14O14P
Molar mass: 1,356.373 g/mol
May treat: Pernicious anemia, Multiple sclerosis, Diabetic nerve damage, Alcoholic polyneuropathy
May prevent: Vitamin B 12 Deficiency