While shooting the last movie in the Maze Runner franchise back in 2016, the actor was run over by a car on set and sustained a number of injuries, including severe trauma to his brain, and he had to have facial reconstructive surgery after the accident apparently broke most of the right side of his face.
Dylan O’Brien has spoken before about how the accident affected him, sharing that it made him realize how important it was to him to “nurture” relationships he’d not placed emphasis on prior.