Your question illustrates a common but pretty irrational approach you share with many other people: fear of showing a problem to a doctor for fear you'll find out it's a problem.
If this were a problem, that kind of problem could land you in plenty of hot water. Fortunately, in your case, I'm fairly sure from your description that you have a harmless lentigo, or sun spot.
Do yourself a favor: show the spot to a dermatologist, who can set your mind at ease about this spot, as well as others you're likely to get if your skin is prone to them. Also, you'll learn good ways to prevent and eliminate them.
Get on the stick, Jackie! You have nothing to fear but fear itself!