Hand movements can be severely affected due to certain medical conditions such as stroke, or as a side effect from the treatments for other diseases such as breast cancer. Here, we propose a solution based on optical fiber Bragg gratings (FBGs) for the monitoring of rehabilitation exercises to recover the hand fine skills, the fingers strength and the precision of movements. The developed sensor was initially calibrated to force, and a value of 18.16 pm/N was obtained for its sensitivity. The sensor was tested for handgrip exercises of precision, oppositional, and lateral pinches, and the results obtained are in accordance with literature, which proved the sensors potential for monitoring this type of exercises during physical therapies. This solution can be further integrated with the Internet of Things (IoT) health systems for a remote digital health solution, as a facilitator for the physical therapies to be performed remotely from the patient's home.