And as a practical matter, it doesn't really clarify the pronunciation of Nguyen unless one knows which English pronunciation of ng you're referring to. I'm just teasing with this pedantry, of course; I understood what you meant. But then, I already knew how to pronounce Nguyen.
What are bruises? Bruises are bluish or purple-coloured patches that appear on the skin when tiny blood vessels, called capillaries, break or burst underneath. The blood from the capillaries leaks into the soft tissue under your skin, causing the discolouration.
The most well known cause of dark circles is the lack of sleep, which is actually very true. Lack of sleep tends to make the skin look paler, dehydrates the skin and lessens the circulation in the skin, which then emphasizes the shadows under the eyes.