7 types of skin spots you should NEVER ignore on your body

3. Dermatofibroma

“A patient will come in and tell me that she’s had this bump that’s been on her skin for years and it never goes away,” Elbuluk says. You’ll find them most often on your arms and legs, and they can be pink or brown. The bump is made up of fibrous scar tissue, which can form as a reaction to something like a bug bite or ingrown hair. Like a skin tag or cherry angioma, these are perfectly harmless. But because it can look like a mole, you’ll want a derm to take a look to determine which one it is, as “moles can change into melanoma, but a dermatofibroma does not,” Pelle says.