Louis is running away from Twitty, he trips and he gets covered in mud (including his back)-- yet a little bit later (when Louis is running away from that group of young girl scouts) his back is almost completely clean.
When Ren said she'd give the "cheesy calzone" to Tugnut, he took it, but when he stuffed it in his mouth, it was filled with veggies and no sign of cheese.
Tawny and several others are next to Louis in the lunch line when the two old guys in his head start a dialog. When Louis comes to his senses a few seconds later, it's Ren who is suddenly next to him.
When the two old guys are talking, Louis subconciously hears Ren's voice saying, "Loius...Louis." Then when the camera shows Louis coming to, we hear Ren saying "Louis" again, but her lips don't move.