Is that B2 or B12?
If B2 only, usually it best to use a Vit B complex so the B's are balanced..

How did you get your concussion?
What part of head was hit, what angle, any whiplash /neck effect factors?

Any PT or chiropractic tried?
[vertigo, a heart beat thumping in my ears] muscle spasms?
[changes in my vision] trigger points?
[spasm for a bit like a small muscle on my shoulder. Also I would wake up and my arm would be numb (sounds silly but never happened before and dont sleep on it)] muscle spasms /pinched nerve?

Those symptoms should be evaluated by expert PT or chiro..might be very helpful for you..
Also upper cervical adjustment if you look into that..