Lord Of The Rings: 10 Movie Mistakes They Hoped You Missed
4. Frodo's Changing Scar
Continuity can be a b*tch. On huge productions like this its someone's job to look out for continuity issues. This might extend to making sure a character has the same costume on from scene to scene, or might just be making sure actors hit the correct mark during each retake. But inevitably things slip through.
During the final showdown on Mount Doom, Frodo gets a little dinged up from his confrontation with Gollum. So badly indeed that he gets a giant cut on the side of his face. As he lies on the slopes of Mount Doom in the hands of his his loyal Samwise, Frodo has a distinctive cut on one of his cheeks. But when he enters the mountain the cut changes cheeks.
The explanations for this is most likely down to the mixed shooting schedule. It was often the case that scenes from the same sequence were filmed at different times over the course of production. Months might have gone by between filming these scenes, and in that time the make up team simply forgot which cheek Frodo had injured... seems like a rookie error.