work your fingers to the bone
From Longman Dictionary of Contemporary Englishwork your fingers to the bonework your fingers to the bone (also work your socks off informal)WORK HARD to work very hard → workExamples from the Corpuswork your fingers to the bone• In those days we got up at 5 in the morning, and worked our fingers to the bone.• His mother had had a hard life - had worked her fingers to the bone bringing up six children.