If the methylcobalamin was causing acne, the most likely reason is that it was working fast to help you (because a larger quantity of usable methylcobalamin was getting through).

If you were to take hydoxocobalamin or cyanocobalamin you would be getting less methylcobalamin (as your body converts the other form to a smaller amount of usable methylcobalamin). And that might make a difference. Might or might not help as quickly or as much, but also might not cause acne.

Another thing to consider is that many people do not metabolize one or more nutrients well. So even though you have been taking them, it may be that you have not been getting the full benefit.

Best wishes,

rose