But the operation meant she survived skin cancer and is now grateful to be alive.
Lily was found wandering around Kidderminster in Worcestershire.
Dab on the sunscreen
If she'd been left untreated, the cancer would have spread and Lily would have died.
Skin cancer among pets is a growing problem.
Vets say cats and dogs need high factor sun cream on their noses and ears in summer just as much as children.