She and Clyde were in a bad car accident in 1933 (Clyde overlooked warning signs of a bridge under construction and flipped the car into a ravine), so it was not just the acid, but also gasoline fire and 3rd degree burns. The bit if acid in a car lead battery would not be enoug to cause this kind of caustic burns if the skin was not broken. They hid in a remote motel in rural Arkansas to nurse her, but had to move soon again due to a screwed up robbery and subsequent killing of a marshall. She spent her last year crippled and in agony before the group was killed in '34.