Help Bump behind ear don’t really know what it is

Patient: A few days ago I found a bump on the back of my ear. It was kinda big and I thought it was a pimple so I was playing with it and picked off the scab and made it bleed. So I thought it was then maybe a bite so I put on after bite on it the next morning I believed it shrink. Its somewhat very tender it sometimes hurts little pain . when I touch it its alittle painful. im not too sure that its acne or what it is. what is it? what do I need to do to get it to go away?

Symptoms: Tenderness, little pain,