This could be an infected duct, a sebaceous cyst, or some sort of skin issue. If you are running a fever, call the doctor right away. If not, you could see if hot compresses help. Check with the doctor if it is not better within the week. You might need an antibiotic. Breast cancer lumps in men and women are deeper in the tissue than what you are describing, so I don't think you need to worry about this being cancer. Breast cancer is rare in men, and is more likely in men with a family history of breast cancer.
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