Non Pulsatile Unilateral High Frequency Tinnitus for 3 Months / Vitamin B12 Low

Hi
I have gradually developed tinnitus, in my left ear, with below characteristics, over the last 3 months

- Unilateral
- Non pulsatile
- High Frequency
- Occasional discomfort/fullness in the ear (developed over the last month)
- Worst in the morning while waking up
- Occasional minor tingling/numbness sensation in fingers and a burning sensation on one particular spot on my hand (exactly same spot - comes and goes). These symptoms have been around for almost a year.
- Occasional fluttering in my other ear only in the morning while waking up (started recently)
- Developed T during a stressful period

Results of various tests

- Blood test indicates Vitamin B12 deficiency (extremely low of 118 pg/ML)
- Audiometry normal (No hearing loss)
- Consulted with 3 ENT specialists and all reported no issue after check-up
- Eventually last week met a Neurologist who has ordered an MRI (even though he believes it will be normal) as part of protocol to rule out vascular reasons

Therapy so far

- Vitamin B12 (Cyanocobalmin) injections - 6 shots over a period of two weeks, ending 27.11.17. No improvement so far

Questions

- Did anyone else have similar symptoms?
- How long does Vitamin B12 therapy take to show results ?
- What could be the potential reason considering these symptoms?