For the past year, I've had this mark that looks like a hickey appear in the same spot on my neck three different times. It's right in the middle of my neck and doesn't itch, hurt, or feel irritated, but I know it's definitely not a hickey. I'm 39 and generally healthy, so I'm nervous because I can't figure out what's causing it. Hydrocortisone cream hasn't helped, and by the time I manage to book a doctor's appointment, it's already gone. It just shows up randomly without warning. What could this be?

Dermat opinion