I got B12 injections in September and my skin started getting bad in October. I stopped the B12 in February when I finally realised that was causing the acne. My skin is soooo much better now, I would Best Vitamin B12 Injection Sites: Where to Inject B12 PA Relief How Quickly Does B12 Shot Work? Duration of Benefits Acne and Vitamin B12 Unexpected Skin Changes? Could It Be B Deficiency? A patient presented with unexplained skin hyperpigmentation as the primary symptom. Surprisingly, the underlying cause turned out to be vitamin B deficiency. This case Cobalamin (vitamin B12) and Folate Deficiency Province of British Columbia