Continuity mistake: When Skylar is packing, one shot of her has one color clothes that she's putting in the suitcase and the next shot of her has different color clothes. This happens two or three times. (00:39:00)
Continuity mistake: Sitting outside a crack house looking for Jesse, Mike and Walt are talking in Mike's car. When Mike says he could just be mugged or shot, the camera is behind their heads. Walt turns his head towards Mike while he's saying this. When the camera angle changes, suddenly Walt is looking out of the passenger window again.
Chosen answer: It is part of the ritual for la Santa Muerte. It is a sign of humility and sacrifice.
djm