An update: I have tried methylcobalamin form of B12, and I have tried it via a transdermal patch. The dose was 500 micrograms. It seems the acne side-effect is still present – there are less acne this time, but they have still formed. In fact, a HUGE inflamed acne formed below my eye (which is a very weird position).
What is interesting is that, since this was B12 absorbed directly into my blood, it indicates that my digestive system is not to be blamed for acne caused by B12 – it seems it is purely B12, and it seems the type of B12 is not very relevant.
Also, the acne that form are unusual. They more feel like elongated hard lumps well below the skin. The skin above them is red and inflamed.
I will switch do daily dose of 10 micrograms. That’s my only hope.