Doesnt sound like Diabetes to me (ive been diabetic for over 20 yrs) get blood checked for STD or STi's
I have diabetes and never had that trouble, I did get ED from diabetes, where I could not get an erection, but never any sores, I think I would go to the Dr. for that one, maybe run some blood test. dont be too surprised if it is something else, I could be wrong but I have had diabetes for awhile and never had a problem like that..... good luck