Hi, Welcome to healthcare magic forum I completely understand the discomfort you are suffering from and according to the symptoms you are describing it is most likely a boil which is due to infection of hair follicle or sebaceous(oil containing) glands with buttocks,face, neck,armpits being most common sites.Since it is foul smelling necrotic debris must have form inside which has burst open. Most common causes of it are: 1. Improper hygiene 2. Lack of proper nutrition 3. Diabetes I suggest you to have hot compressions of the affected part 3-4 times a day, wear loose clothing, avoid using soap with chemicals at the affected part, you can use any anti-bacterial soap for cleaning the infected part, Another possibility is an abscess, and in both a foul smelling boil or abscess, lesion should be drained along with a course of antibiotics. I suggest to get the lesion examined by a physician for drainage of the lesion and further management. Importantly, don t try to press or squeeze the infected site it will lead to worsening and spread of infection. Kindly rate my answer if you find it useful.Feel free to ask any further queries.Take care. Regards, Dr. Tushar Tamboli