Factual error: When Bradley Cooper calls Louis C.K. he asks him, "Where are you?" Given he's just called him on his office number, rather than a carphone, he knows exactly where he is.
Factual error: In the scene where Irving goes to one of his dry cleaning locations and retrieves a gun and some money out of his safe, the money seen is quite obviously a more recent looking print with the spacing and look of a "large faced" bill, as opposed to money from that era with small faces on the bills.
Factual error: In the scene at the airport when the jet arrives, a Diamond Da-40 is seen in the background. This aircraft was not made until the early 90's, a decade after the scene takes place.
Revealing mistake: When young Irving is breaking the store windows, you can see some of them shatter before the rocks hit them, in one case before the rock even leaves his hand.
Factual error: They mention that the mayor adopted one of his children from the Boys and Girls of America, but the organization was only known as the Boys Club of America until they changed their name in 1990.
Continuity mistake: When Irving goes to see Carmine near the end of the film, his glasses start out being tinted, but when he takes them off, as Carmine hits and kicks him, the tint has gone; even outside they're tint-free.
Factual error: In the opening scene, Christian Bale is arranging his comb-over. On a nearby table, a can of present day Elle-Net hair spray can be seen.
Factual error: The scene at Teterboro Airport shows a tri-jet Dassault business jet. The first version of that plane was the Falcon 50, which wasn't certified until 1979. The movie takes place in 1978.
Answer: She wears a neck brace because she was in a car accident, she mentions the state of the car during the conversation.