Trivia: When Teddy enters the lighthouse, as soon as he begins to climb the spiral stairs, the camera follows his movement from in front of him. However, as Teddy and the camera wind around the stairs, the wall behind also appears to move with them, as though what is REALLY moving is only the staircase itself, rotating on its central axis. Yet another point (added to the various disappearing glasses/bottles) that adds to the general 'insane' feel of the film.
Trivia: During the ferry approach at the start, we are shown Shutter Island. In actuality this is a combination of Peddocks Island (the decaying brick buildings), Maine's Acadia National Park, Massachusetts' Medfield State Hospital, and Turner Hill Country Club's Rice Estate (located in Ipswich, MA), which were combined via CGI. Additionally, the mountainous region of the island (shown as the ferry approaches) was also CGI, and added in post-production.
Trivia: The scene where all the soldiers are shot along the fence is historically accurate, though there is debate on the exact numbers.
Answer: The bandage is a symbol indicating when and when not Teddy is caught in his delusions. When the bandage is on he is delusional, thinking he is the marshal finding out all the dark secrets of the facility. When the bandage is absent he is lucid and aware of his past crimes and his own delusions.
Wrong. It's on the whole movie until he takes a shower. The bandaid is off but yet that's the scene where he runs in the lighthouse thinking he's the Marshall still. Did you watch the movie at all?