What could be the cause of an inner-thigh scar from no trauma? (photos)

About 4 months ago I noticed a small scar on my inner thigh that started at the top of my right inner thigh next to my scrotum. It was about an inch long and one-quarter inch wide. It has since grown slightly. The color is a purplish-red with no symptoms or itching, swelling, peeling. It's simply a very slow-growing scar from what I can tell. I want it to stop growing and heal. It looks like a keloid scar.