Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. As per your description it seems like something like carbuncle or minor abscess. It is nothing but local infection and pus collection underneath the hair follicles. No need to worry as it can be easily cured by antibiotics. You can start a short course of antibiotics like ampiclox for five to seven days. Apply topical antibiotics like mupirocin after cleaning with soap and water. Make sure that his blood sugar level is well controlled as uncontrolled diabetes can worsen the symptoms. Hope I have answered your query. Let me know if I can assist you further.