My scalp is pink now 2 weeks after surgery. Why is it that way? (photo)

Some people have skin that easily turns pink when it is traumatized. I can detect these patients in advance by having them scratch their forehead with their fingernails. If the scratch mark turns pink within 5 miniutes, it means that the skin is histamine positive and these patients will often retain some pink coloration for a longer time than the non-histamine positive patients