The incident happened early in the evening when her own dog was attacked at the Wisewood Inn, in Loxley, and it has now sparked a police appeal for information.
A South Yorkshire Police spokesman said: “It is reported that on 12 February at around 7.45pm, the victim was sat inside the Wisewood Inn when her dog was attacked by another dog. When she attempted to separate the animals, she was bitten on the hand.
“Her dog suffered injuries that required treatment from a vet, and she has suffered nerve damage to her finger.
They added they now want to speak to anyone who witnessed the incident, or anyone who can provide information about what happened.
Anyone with information is asked to call 101 quoting incident number 612 of February 12.