Why Do I Have A Contusion And A Swollen Knot On My Forehead Close To My Hairline?

I have a contusion on my forehead close to my hairline from an auto wreck that keeps filling up with fluid which in turn, drains down into my eye and cheek area (black and blue). CT scan showed no brain bleed. Tomorrow will be the 5th day after my injury. When can I expect the swelling knot on my forehead to flatten out?