I have a lump in the outside of my anus what could it be?

Hemorrhoid or: Skin tag. Both are benign. There are other possibilities as well. Hemorrhoids are dilated vessels that can bleed from time to time but not as common to see in someone 21. skin tags are overgrowths of normal epidermal skin and are benign. An simple rectal exam and an anoscopy in office can hem diagnose the issue. Other causes include anal warts or an abscess.

Anal Abscess: If it is painful to touch it is possibly an anal abscess, a painful condition in which a collection of pus develops near the anus. Most anal abscesses are a result of infection from small anal glands. http://www.webmd.com/a-to-z-guides/anal-abscess

Anal mass: hemorrhoid, abscess, tumor to name a few. see a doctor