The size and feel of the lump can vary, but it is generally mild, short-lived, and part of the normal injection response rather than a cause for concern
First described back in the 1950s, acne erupts in about one in ten people within days or even hours of getting an injection of vitamin B12, which then disappears rapidly when injection treatment is discontinued. At the time, we had no idea what the mechanism might be, and the problem remained unsolved until just a few years ago when we finally figured it out: Vitamin B12 modulates the gene expression of the skin bacteria that cause acne
Most medical documents indicate you might experience any of these: Mild diarrhea and/or upset stomach Difficulty breathing or swallowing Weight loss or weight gain Nervousness or restlessness Nausea or vomiting Headaches or migraines Paresthesias (tingling sensations) Rhinitis (chronic sneezing or a congested, drippy nose) Skin reactions, such as rash, itching, swelling, blisters, or pain at the site of injection Light joint pain Lightheadedness or dizziness Chest pain or discomfort Low blood potassium levels Irregular heartbeat Chills, night sweats, fever, or hot flushes General feeling of sickness However, people often fail to recognize that many side effects of vitamin B12 injections are consistent with B12 deficiency itself
10.1111/jpi.12463
