Vitamin B12 Deficiency Vitamin B12 deficiency happens when the body does not have enough vitamin B12. Vitamin B12 is important for making healthy red blood cells and keeping nerves Acne] Beware of vitamin B12! : r SkincareAddiction Can Vitamin b12 Injections Cause Nasty Rashes? Vitamin B12 shots: Uses, benefits, and side effects Vitamin B12 Deficiency Harvard Health Vitamin B 12 intramuscular injections are also used therapeutically to help restore energy and combat various symptoms related to such deficiencies. Vitamin B 12 is essential to the development of healthy blood cells, nerve