In the opening scene, a mark can be seen on the right side of Dean's forehead. Later, when Martin punches him, Dean has a cut in the exact same spot. It appears they forgot to remove the wound makeup between takes.
In this episode Sam tells Amelia he is leaving, but in a later episode he sneaks out in the middle of the night.
When Benny starts talking to Martin, who has Elizabeth tied to a chair and is holding a knife to her neck, the blade of the knife is facing away from her neck. In the next scene Martin is holding the blade correctly.