Chillingworth's appearance, similar to the appearances of other characters in the novel, is linked figuratively to his inner motives and characterization. At the beginning of the novel, Chillingworth disguises himself as such to hide the fact that he is Hester's husband. His heart is set on getting revenge, and when he becomes the personal doctor for Dimmesdale, his appearance becomes a bit more cold and grave. However, at the end of the novel after Dimmesdale dies, Chillingworth no longer feels that he has any purpose--the object of his revenge is dead and Hester has already made it clear that Chillingworth does not have the power to make her feel a sense of guilt or remorse. So Chillingworth shrivels and dries up physically to metaphorically represent the withering away of his spirit. He has harbored evil thoughts for so long that these thoughts have consumed him.