B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics Feeling worse after B12 Injection: Answering concerns. La Vie Med Spa Injections in arm Pernicious Anaemia Society Lets do my first B12 injection together This is something Ive been nervous about for a long time, but today I finally did itand it honestly wasnt bad at all. I used the Union Medico needle guide Left arm numb Causes, Diagnosis and Treatment