There is a hard and painful lump next to the anus. You should register with the Department of Proctology, which often suggests that you may have the following types of anal diseases. First, perianal abscess, which often has a subcutaneous mass next to the anus, accompanied by significant swelling and pain. If the mass is superficial, there will be skin redness and swelling. Second, internal hemorrhoids prolapse outside the anus and cannot be retracted into the anus by themselves, and are embedded outside the anus, resulting in obstruction of blood return within the hemorrhoid nucleus, causing painful swelling of the nucleus. Thirdly, thrombosed external hemorrhoids. Due to the rupture of the blood vessels of external and internal hemorrhoids, blood overflows outside the blood vessels and stagnates in the local area, forming thrombus, which stimulates the peripheral nerves under the skin and causes severe pain.