One of several possibilities comes to mind. Either you have an allergic reaction to a new product/drug you are using, you have a skin infection or granuloma anulare which looks like bumps that form a circle. Would suggest you go see a dermatologist as this is not normal nor should you have to put up with the itching.
With regards to a skin allergic reaction, have you started using new products on the area that now itches? Consider a new lotion for your skin, shampoo or conditioner for your hair. Ask the dermatologist for her / his recommendations.
Or you have an infection on your skin, possibly because of your elevated blood glucose. Or are you stressed out about something? When the blood sugar of people with diabetes is out of normal range, they are much more susceptible to infections so deal with this quickly. If you are itching, you may break the skin and get an infection from normal bacteria on the surface of your skin. Ask the dermatologist about these issues.
I would suggest you consider changing the doctor you see for diabetes. A diagnosis of diabetes requires careful regulation of your blood glucose and A1c (glycosylated hemoglobin) to prevent long-term complications. Find a doctor that has a greater interest in your diabetes and make an appointment to see a registered dietitian to talk about your eating plan. A lot has changed in diabetes care.