Why does Andrew laeddis have bandaid on his forehead when he is in the boat?

In "Shutter Island," Andrew Laeddis has a band-aid on his forehead while in the boat to symbolize his mental and emotional wounds. It serves as a visual cue to his struggle and the trauma he has endured. The band-aid reflects his fractured psyche and the need for healing, both physically and mentally, as he grApples with his past and the reality of his situation.