We have been developing the Robot Mask with shape memory alloy based actuators that follows an approach of manipulating the skin through a minimally obtrusive wires, transparent strips and tapes based pulling mechanism to enhance the expressiveness of the face. For achieving natural looking facial expressions by taking the advantage of specific characteristics of the skin, the Robot Mask follows a human anatomy based criteria in selecting these manipulation points and directions. In this paper, we describe a case study of using the Robot Mask to assist physiotherapy of a hemifacial paralyzed patient. The significant differences in shape and size of the human head between different individuals demands proper customizations of the Robot Mask. This paper briefly describes the adjusting and customizing stages employed from the design level to the implementation level of the Robot Mask. We will also introduce a depth image sensor data based analysis, which can remotely evaluate dynamic characteristics of facial expressions in a continuous manner. We then investigate the effectiveness of the Robot Mask by analyzing the range sensor data. From the case study, we found that the Robot Mask could automate the physiotherapy tasks of rehabilitation of facial paralysis. We also verify that, while providing quick responses, the Robot Mask can reduce the asymmetry of a smiling face and manipulate the facial skin to formations similar to natural facial expressions.