Watch the scene where the owner of the basement they use for fights, fights with Brad. He hits him repeatedly on the mouth, causing a lot of bleeding. You see Brad with a lot of blood on his mouth, then without any, and then with a lot of blood again..!
Actually, during that scene, when Brad is laying on the floor all bloody and stuff, they switch to Ed Norton's face for an instant. Very quick editing but if you freeze frame the DVD, you'll clearly see that for about .5 of a second, its Ed Norton laying on the floor with a bloody mouth. Another clue maybe...
Mike
Well, Actually I really doubt that's a slip up for the following reason:
Later in the movie Tyler tells the narrator that he looks the way the narrator always wanted to look (in that "I am what you always wanted to be" scene) and I really doubt the narrator wanted to look injured. Also to further show my point, Later in the film (about one scene later, when he goes to work) you see the narrator was his mouth all injured. So I think this is more of a plot point then a slip up
That's a good observation and it would make sense, but, I think the non-bloody mouth part is too quick for it to be useful for the plot. It's just a mere slip-up!