Breastfeeding is experienced as an existential journey, and breastfeeding difficulties put mothers in existentially vulnerable situations. For care to be caring, it must be based on the mother's breastfeeding story. Previous research show that healthcare professionals struggle to perform individualised breastfeeding care. The Existential Breastfeeding Difficulty Scale (ExBreastS) was developed to support an existential focus in caring dialogues and was introduced in child healthcare in Sweden. The aim of this study is to describe child healthcare nurses' lived experience of how the Existential Breastfeeding Difficulty Scale (ExBreastS) influences the caring dialogue. Seventeen child healthcare nurses with experience in using ExBreastS as a basis for caring dialogues with breastfeeding mothers were interviewed, in groups, pairs or individually. The interviews were analysed using a thematic analysis based on descriptive phenomenology. The results show that the caring dialogue becomes re-evaluated when using ExBreastS because existential aspects of breastfeeding is acknowledged. ExBreastS also visualises new perspectives of the mother's breastfeeding experiences. However, the use of ExBreastS also risks overshadowing the caring dialogue when the nurses focus too much on the instrument. The use of ExBreastS supports caring dialogues-and caring care-by highlighting the existential aspects of breastfeeding/breastfeeding difficulties and the uniqueness of every mothers' breastfeeding experience. However, the instrument sometimes evokes a vulnerability in the nurses that calls for support from the care organisation.