About 1 in 10 people aged 55 years and over are affected by PN, and the most common cause is diabetes
I have had that pain on but a handful of occasions in the over six hundred B12 monthly injections given since 1972
Risk Statement: Administration of subpotent Hydroxocobalamin in infants, pregnant/breastfeeding women, and elderly populations are at risk for vitamin B12 deficiency and there is a reasonable probability they could experience adverse events including muscle weakness, neurological peripheral neuropathic numbness or pain, vision loss, and psychiatric disorders (depression, memory loss)
The difference is immediate and perceptible
(PubMed) Yuan S, Mason AM, Carter P, Burgess S, Larsson SC