Don't discount using prednisolone in these cases because the inflammatory cascade plays an important part in chronic pancreatitis
What is the recommended treatment regimen for vitamin B12 deficiency using B12 injections?

Side Effects Of VITNEURIN INJECTION Common Skin irritation and/or pain around the injection area Bruising around the injection site Mild nausea, vomiting, abdominal pain, or loss of appetite Headache or sleepiness Numbness in the hands or feet, clumsiness, or difficulty walking Hives Heartburn Fatigue Sore throat Rare Stop receiving VITNEURIN Injection and consult your doctor immediately if you experience any of the following side effects: Symptoms of an allergic reaction may include skin rash, itchiness, nausea, sweating, a feeling of warmth, tingling, weakness, tightness of the throat, pain in the chest, a fast heartbeat, difficulty breathing, faintness or swelling of the lips, face, tongue, throat, hands, or feet Severe pain or inflammation of the feet, knees, hands, or elbows Sneezing Flushing, severe rash, temporary itchiness Blue discolouration of the skin Bleeding Prolonged stomach pain Severe dizziness or drowsiness Muscular paralysis Low blood pressure Prolonged nausea or vomiting Restlessness Scaling of the facial skin Inability to focus the eyes How To Manage Side Effects Headache Rest and relax

Theres no single right answer here
Clean the injection site area and vial top with alcohol swabs