B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics Bruise After B12 Shot B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics Can Vitamin b12 Injections Cause Nasty Rashes? Bruising with your injections? It is totally normal and usually nothing to stress about., Heres a quick summary on this common experience!, Why it happens:, A tiny capillary gets nicked, Needle Feeling worse after B12 Injection: Answering concerns. La Vie Med Spa