Just after Knoll has been beaten up we see Elwood sitting next to him. As Elwood switches on the light, we see that the left side of Knoll's face is covered in blood. After Elwood applies the bandage, the blood on his face has changed with much less blood on the left side. The blood was never wiped off.
The hand that lights the lighter in the cooking scene is the director, Gregor Jordans' hand. It says this in the DVD's audio commentary.