According to a study published by the American Physiological Society, proline and arginine supplementation can help heal wounds in diabetic patients.
Diabetic ulcers are a common problem among diabetic patients. It is
estimated that approximately 80% of such patients undergo lower leg
French researchers found that diabetic rats on a high protein diet
with arginine and proline — specific molecules found in protein — showed
better wound healing over rats fed either standard or high protein food
without arginine and proline supplementation.
So I guess the lesson is to eat more protein specifically which has these supplements.