A person's appearance is influenced by his parents, and may also be influenced by the previous generation on both sides of his parents. For example, there was once a person in his mother's family who had dimples, but they didn't appear for several generations, and maybe they were suddenly passed on to you.
A person can't be very much like his father or mother. Maybe his face is like his mother, but his eyes are like his father, his nose is like his uncle, and his skin is like his uncle. In short, many different genes are mixed together.
Some people look like their fathers when they are young, and grow up like their mothers. Some people look like their father when they are thin and their mother when they are fat. This is because this person and his parents have different genes.
Back to Andy Lau's face, his nose is like his father's, his eyes and face are close to his mother's, and the genes of different ancestors have created a unique Andy Lau face.