Don’t impulsively deem any protruding bump as a skin tag; after all, there is an overwhelming number of things it could be—moles and seborrheic keratoses can closely resemble skin tags. Even worse, it could be something that requires medical treatment such as genital warts (possible indication of a sexually transmitted disease). Some growths could also be an extension of glands on the skin, and they can get infected if you’re poking at them at home. As a rule of thumb, if the tag is pigmented, see a dermatologist to get it evaluated. And here are 11 other skin mysteries you should know about.