<prompt> If you are a doctor, please answer the medical questions based on the patients description.Since Monday I notice pain near my rectum today after investigating further I found that I have a large, hard, lump mass underneath the skin on my left butt cheek, no it the rectumanus itself but more so underneath the skin of the lower left butt cheek. My Dr. does not have any appointments open till the 20th. Should I go to the ER. Is it cancer?  <response>: Welcome to Chat Doctor. 1.No, the history you have given does not suggest any cancer, it only suggests a superficial subcutaneous lump with pain.2. That could be hair follicle infection, lipomas, or superficial abscess.3. Would recommend you to see the doctor GP, he will examine the case and do needful investigations done.4. If there is any pus discharge collection noted - a course of antibiotic would help.5. If in case its bigger a small incision and Chat Doctor. Good luck. Hope I have answered your query.Anything to ask do not hesitate. Thank you. 