Since last fall I've gotten this thing that looks like a hickey pop up in the exact same spot 3 different times. Right in the middle of my neck. However, I know for a fact that it's not a hickey. It doesn't itch, hurt, or anything. I'm nervous because I'm not doing anything that would cause this. I'm 39 years old and in decent health. Hydrocortizone cream doesn't help. It's difficult to get into the doctor because by the time I've made the appointment and finally get in, it goes away. It pops up unannounced and seemingly without being prompted.

It sounds like you're experiencing something like a spontaneous bruise or a small blood vessel burst in that area. These can happen without any obvious cause, especially if you're in good health. If it continues to appear, it might be worth discussing with your doctor to rule out any underlying conditions, even if it's not causing pain or discomfort.