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.
You may not have noticed it, or it shown visibly. It can go straight to the yellow/greenish colour and not have dark bruising at all. If there are no signs of infection (tenderness/soreness around the wound, warmer to the touch, puss, smell, discolouration of the wound, etc) then it's probably bruising.