My four year old girl has a rough patch of skin, directly over one of her vertebrae. It is slightly raised, almost a little fatty, and matches the color of her skin. It is about 1 circumference. I have noticed that the vertebrae, which is just below the mid back, is a very prominent vertebrae. I always assumed the skin was irritated from the vertebrae rubbing up against wherever she was sitting, but my mother in law discovered it and was concerned, so I started looking at it. I plan to take her into her pediatrician.