bushwick b12 injection Vitamin – Skin Spa New York 10 Pack - B12 Intramuscular

Medical professionals recommend that these injections should only be used during pregnancy when clearly necessary, and the risks and benefits must be carefully evaluated by a healthcare provider

Kanasaki K, Kumagai A

Differentiating B12 from Folate Deficiency Both deficiencies cause macrocytic anemia with large red blood cells

Not sure it would occur that fast, but they seemed to brush it off so I doubt it would prevent you from getting a second dose, assuming you have educated medical personnel administering the dose and that you did not have anaphylaxis with the first dose

It's crucial to stick with your prescribed schedule and not adjust your dosing without medical guidance