I would suggest you try Dia-IonX. It helps with many of the common symptoms of diabetes and may decrease the itchiness. It may help you to achieve a lower dose and keep your dog better regulated. There are some other things that I find synergistic with Dia-IonX to produce faster healing. Feed only wholesome diabetic approved food and treats. With each meal give digestive enzymes, and a probiotic, MSM, and a fish oil supplement daily. Try to provide regular moderate exercise daily; it helps to lower blood sugar by facilitating its entry into the muscles.
Be sure to be watchful for signs of low blood sugar (weakness or shakiness) and keep in contact with your veterinarian in case you need to adjust your insulin dose. If the body starts to make more functional insulin then your current insulin dose would be too high. Please let us know of your progress and if you have any further questions.