can b12 injections cause bruising What Not to Do After a Injection — Essential Tips Bruising after B12 injection ?

You wont be guessing

Priapism is a prolonged erection lasting more than 4 hours that does not resolve on its own

Supports Fetal Nervous System Development Vitamin B12 is essential for the development of the fetal nervous system

The most commonly reported adverse events were mild-to-moderate headache and gastrointestinal effects including flatulence and mild diarrhea

You should not take it if: For a full list of warnings and precautions and a list of ingredients contained in this medicine, see the patient information leaflet

As today has gone on, it's become more apparent that I am likely coming down with a virus....so that may be why I don't feel well, and have also been fairly stressed recently, so it could be something that sorts itself over time