Does anyone else's V have some darker areas on the outer edges of their lips? For quite some time Ellie has had a small area on both sides of her lips (the bottom edge of the lip, not inside) that is like a really dark greyish color. The skin does not feel any different. The only thing I can think of is maybe some long term tissue irritation from a treat fetching game we play on the concrete driveway. It is one of her favorite games and she often looks like she is grinding her mouth against the concrete to catch the treat as it rolls. She has never bled or anything like that. This is just my only guess as to cause.