Quick science lesson: dark circles are actually dilated blood vessels. Because the skin around your eyes is so thin, your blood vessels underneath—when dilated—become visible. Baggy eyes are typically a sign of dehydration. Both are the result of not sleeping enough, having one (or three) too many mojitos, or simply a gift from mom and dad (thanks, genetics). Regardless of where they came from, here’s how to get rid of baggy eyes.