I noticed a lump on the outside of the anus (At the rim of it) two days back. There is slight pain at touch. No pain otherwise, nor during the passing of stool. No bleeding or any other unusual symptoms. But the lump appeared suddenly and is about the size of my little fingernail. I am very anxious as to what it is. Can I wait for it to heal by itself or should I visit a physician? (I think it may be a perianal hematoma)