Knowledge workers suffer from wrist pain due to their long-term mouse and keyboard use. In this study, we present CareMouse, an interactive mouse system that supports wrist stretching exercises in the workplace. When the stretch alarm is given, users hold CareMouse and do exercises, and the system collects the wrist movement data and determines whether they follow the accurate stretching motions based on a machine learning algorithm, enabling real-time guidance. We conducted a preliminary user study to understand the users' perception and user experience of the system. Our results showed the feasibility of CareMouse in guiding stretching exercises interactively. We provided design implications for the augmentation of existing tools when offering auxiliary functions.