I discovered a cyst tonight that appeared out of nowhere behind my right ear right before the hair line starts. I'm trying to find out if it is something serious or if I'm worried for nothing. I'm just concerned because I was born with a cyst behind the same ear and it had to be surgically removed. At the current moment it doesn't hurt and it's about the size of a small peanut. Does anyone know what this is? Should I even be concerned?