Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. Diabetes melitus is often associated with prolonged non-healing infection as diabetes make a person immunocompromised. In my opinion you are having balanoposthitis which is the inflammation and infection of glans penis and foreskin, and in your case it seems to be fungal infection since fungal infections are fairy common in diabetics. I would recommend you to start topical anti-fungal cream mixed with topical steroids and apply it over your glans penis and foreskin twice daily and keep a good hygiene, moreover try to have your sugar levels in control. My last advise for your would be to get circumcision done to get rid of these recurrent infections but since you are diabetic so you should have achieved good glycemic control both before and after circumcision. Hope I have answered your query. Let me know if I can assist you further.