Permanent Facial Bruising

My husband has bruising on his face that was caused during his high school years and they have never gone away... its only on the right side of his face... Mainly the forehead, side of the forehead and eye socket area... it was cause by 3 different incidents ie. falling over and childhood fights etc. and the bruising has never gone away... what could be causing this... he has bruised on his body before from sports etc and all other bruising heals and goes away as per normal...
These bruises are over 15 years old.. what could be causing this bruising not to go away???