Brief Answer: Could be complicated because of diabetes. Detailed Answer: Hi, Thanks for posting your query. The deposit under the foreskin is called smegma, and it is a natural thing, but however needs cleaning on a regular basis, like, once in two days at least. This should not cause any discomfort or pain, since you are experiencing pain, I suspect you might be having an added infection in the area, which you are prone to, as you also have diabetes. My suggestions to you would be, 1. Clean under the foreskin twice a day, preferably with povidon iodine solution. 2. Keep the penis dry. 3. Clean the penis well after each sexual intercourse. 4. Consult a general surgeon or urologist or a dermatologist for further evaluation. 5. You may require a culture and sensitivity test to see what type of infection it is. Further treatment can be advised based on the reports. Hope this answers your question. Please feel free to ask me if you have any doubts. Wishing you good health. Regards

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