3.Headaches
Vitamin B12 deficiency often leads to neurological side effects. The most common one being headaches. If the reason is lack of B12, the headaches will most likely be migraine-like, even if there is no migraine history.
Facial pain can also be a sign of vitamin B12 deficiency. So, it is possible to feel pain under the eyes or in the cheekbone area from time to time. Most often, only one half of the face is aching.
Another type of pain that may be associated with B12 deficiency is one that appears in the forehead. Unpleasant sensations may intensify over time; then the pain increases as if “descending” to the wings of the nose.