I have seen loads of threads here with people saying how great they feel after B12 injections.....
I have awful heavy periods, so was tested for anaemia, iron levels were fine, but B12 was 165. So, I had the loading doses in December and immediately after the first injections started to get big boil type spots. They got worse and more wide spread, saw GP who said they were allergic cysts and not to have any more B12 injections and not to try tablet form supplements either.
I am still covered in massive spots, along with black heads and white heads. They are on my scalp, neck, back, chest, stomach, tops of arms and shoulders, hips and a particularly nasty one hiding in my pubic hair 
I am diabetic which made them slow to heal, so my GP prescribed antibiotics....which I was allergic to
so I had to stop those and was given steroids. The steroids did help with the biggest ones, but I've had two courses now and once they stop, the spots come back just as bad.
I thought maybe this acne would just run it's course and gradually go away once the B12 was out of my system, but it is just carrying on and on.
Anyone else had any experience of acne caused by B12? Or allergy to B12? I found this and I am allergic to most of the things on the list (and tons more) but would love to know how much longer this is likely to last, GP isn't sure.