The invention discloses a computer-implemented method (1600) of determining a location of a personal care device with respect to a skin surface of a subject. The method comprises receiving (1602) data representative of a measured curvature of the skin surface within a first region of the skin surface of the subject, with which the personal care device is in contact; determining (1604), by comparing the measured curvature with curvature information for a plurality of regions of the skin surface of the subject contained in a database, an indication of a location of the first region of the skin surface on the subject; and performing (1606), based on the determined indication of the location of the first region, an action in respect of the personal care device. A processing apparatus, a system, a personal care device and a computer program product are also disclosed.