Insulin pen needles are intended for single use only but it is known that a significant proportion of people with diabetes do re-use needles.
Why is my blood glucose high?
Needle Reuse - BD
Clinical Implications of Lipohypertrophy Among People with Type 1 Diabetes in India
Where can I get a list of all the types of insulin pen needles and syringes that are available on the market? - Quora
Why is my blood glucose high?
Insulin Pen Needles
A Coloured Pen Needle Education System Improves Insulin Site Rotation Habits: Results of a Randomized Study
Your Guide to Diabetes Supplies: Insulin Pens – Sarah Hormachea
Diabetology, Free Full-Text