No, this is not what Leatherface looks like underneath his mask.
On the contrary! Marlene Dumas used a photo of Swedish actress Ingrid Bergman for inspiration. Ingrid was one of the most beautiful mid-20th century movie stars, notable for her roles in "Casablanca" and "For Whom the Bell Tolls." That explains the name of the painting. Marlene Dumas is famous for using iconic images from 20th century Western society and she used an iconic photo of Ingrid from the movie for this work.
Before becoming a movie and a painting, FWTBT was originally a novel written by super famous novelist Ernest Hemingway. The novel describes the brutality of the Spanish Civil War. Ernest wasn’t a huge fan of Hollywood, let alone selling them his stories. About dealing with the movie industry as a novelist he once said: “You throw them your book, they throw you the money. Then you jump into your car and drive like hell back the way you came.”
After he sold them FWTBT he got a little more involved though. I guess he absolutely adored Ingrid Bergman, so he tried everything in his power to make sure she was gonna be the leading lady in the movie. He went as far as sending her a copy of the book with the inscription “You are the Maria in this book.” Bam!
Oh and by the way, the Metallica song was also inspired by Hemingway's novel.