I have gone through your post in which you mentioned that you have vitamin B12 deficiency
I usually prescribe Nervijen
injections to my patients.
Before deciding on the duration of treatment, it will be better to try to find out the cause of your Vit. B12 deficiency (either due to inadequate dietary intake or due to inadequate absorption of Vit B12 in the intestine)
Vit B12 is found in most animal derived foods like fish, meat, eggs, milk & milk products.
So...once you have achieved symptomatic relief after taking injections, switch on to these dietary sources.
Wishing you a Healthy Life.