Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. This is caused by irritation of stomach mucosa by certain food or medications, stress, and smoking. It should be treated by changing lifestyle habits first and in severe cases, medications or surgery may be required. This is very likely an inflamed pilonidal sinus (which is a small abscess that occurs in the cleft at the top of the buttocks). This usually contains hair, dirt, and debris. It can cause severe pain and can often become infected. If it becomes infected, it may ooze pus and blood and have a foul odor. In your case, there is obviously infection so treatment should be followed. You need to clean this wound properly and see a doctor who will determine if surgical incision and drainage is required or antibiotics. Later, when inflammation subsides, you may need surgical procedure as a permanent solution. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Ivan R. Rommstein