I can't remember ERM, do you have low HCL or another reason why your digestion of B12 would be impared? You can get addequate B12 from eggs and any animal based protein if your stomach and small intestines are working properly. If they aren't then I might try it once at a very low dose just to see.
I spoke with the doctor today and she said the reason that she doesn't usually do blood work for B12 is because the blood can show adequate levels but it's not getting into the cells. She likes to try a little and see if people show improvement over the blood work.