Is the injecting of insulin harmful in the long run?

My mother is a diabetic patient. She 67 years old and takes 36 units of insulin in the morning and 14 units in the evening. Does insulin cause any harm in the long run? If yes, how serious is it? My mother injects herself on her thighs. I think her skin may be getting a lot of punctures, is there an ointment she can use for this?


Insulin injections need to be given with due precautions of sterilization of the affected area, using disposable needle and syringe, avoiding injecting same area. These injections may lead to injection abscesses, atrophy locally or pigmentary changes.