What are those pimple stuff in your ear that hurts and crusts over later? (Disgusting i no)?

You know when your ear is oily and than next day there is a bump and its there for like 3 days and if you scratch it it bleeds. But if you leave it alone it crusts over and its all good. What are they? How to prevent? No, I don%26#039;t have them just curious.|||Pimple .. Zit .. Just wash your ears with antibacterial soap|||Boil.