Hello,
I would like to tell you that you should not be that worried about
Vitamin B12 allergy. Its a very rare condition and there is no treatment for this, as it will automatically resolved and you do not have to take any kind of medicine for that apart from discontinuing Vitamin B12.
Coming to your second question, Vitamin B12 is the only water soluble vitamin that can be stored in human
liver. maximum capacity of the liver to store B12 is about 2 mg, which is sufficient for 2 to 3 years.
Excess B12 will automatically be excreted through
kidney in urine and there is no way to eliminate excess B12 from your body.
If i were your doctor, i will check your Uric acid level in blood for
Gout and prescribe you medicines to reduce uric acid level, because that should be your first concern.
Do not take B12 tablets, if its level is within normal, so you should check your B12 level and if its borderline, start eating dairy products more and have some boiled eggs in your breakfast, but avoid high protein diet as well to control your uric acid level.
Hope this will help you and get back to me anytime if you have any queries...