I would associate a red face with anger and a white face with fear. And although I think I know the answer, at this point in the novel, I don't know that it's possible to know whose face was what color. All we know of the relationship between Darcy adn Wickham is what Wickham has told Elizabeth and then Bingley and Caroline's blind defense of Darcy (both of them admiting that they don't know any facts in the matter.) They seem to think Darcy has a right to be angry, but according to Wickham's story, so does he...