Call your health care provider immediately if you are experiencing any signs of an allergic reaction: skin rash, itching or hives, swelling of the face, lips, or tongue, blue tint to skin, chest tightness, pain, difficulty breathing, wheezing, dizziness, red, swollen painful area on the leg
That's a fast track to destroying them
Take B12 in the morning rather than evening, as it supports energy metabolism and may be mildly stimulating for some people
The primary concern is reduced effectiveness rather than immediate harm, but you should obtain a fresh prescription to ensure adequate diabetes control
Some individuals may experience mild injection site reactions, such as redness or swelling