Always good to have a reason I have also had this happen when my folate was low , it may be worth you getting it checked I had self inject my B12 every 4 weeks for the last 20+ (cannot really remember how long accurately), and 2 months ago got a similar 'electric shock tingling' all over my body - head, face, arms, hands, legs, feet etc within a couple of minutes of injecting, which lasted about 3 seconds or so
Patients using any formulation should select a time that fits naturally into their daily routine to maximise long-term compliance
A recent meta-analysis of 12 observational studies found that higher dietary intake of vitamin B 12 was associated with a 23% lower risk of depression compared to lower intakes, but stratifying the data revealed a significant protective association in females, not in males (99)
Plant J 58:437449
investigators considered them unrelated, but no long-term oncology safety data exists)