An applicator, comprising: at least one treatment composition component configured to selectively deposit a treatment composition at a deposit location on the portion of skin; and a discontinuity identification component operably coupled to an electromagnetic energy detector, the discontinuity identification component including circuitry configured to monitor a level of one or more parameters that are generated by the electromagnetic energy detector and associated with reflection of an electromagnetic energy interrogation stimulus from a portion of skin as the applicator traverses the portion of skin and to control the at least one treatment composition component to selectively deposit the treatment composition to the deposit location on the portion of skin based on one or more inputs indicative of a decrease in reflection of electromagnetic energy interrogation stimulus from the portion of skin at the deposit location, wherein the discontinuity identification component is configured to measure a baseline reflectance as the applicator traverses the portion of skin that does not include the region of interest, wherein, as the applicator is moved from being over the portion of skin that does not include the region of interest to being over the first edge of the region of interest and then being over the region of interest and then to a second edge of the region of interest, the reflectance level transitions from the baseline reflectance level to a decreasing reflectance level, reaches a lower reflectance level, transitions from the lower reflectance level to an increasing reflectance level, then to the baseline reflectance, wherein the discontinuity identification component is configured to identify the decreasing reflectance level indicating an increase in absorption of the electromagnetic energy interrogation stimulus from the portion of skin at a deposit location, to deposit the treatment composition in response to identifying the decrease in the reflectance level from the baseline reflectance and to stop depositing the treatment composition in response to identifying the increase in the reflectance level from the lowest reflectance level. at least one treatment composition component configured to selectively deposit a treatment composition at a deposit location on the portion of skin; and a discontinuity identification component operably coupled to an electromagnetic energy detector, the discontinuity identification component including circuitry configured to monitor a level of one or more parameters that are generated by the electromagnetic energy detector and associated with reflection of an electromagnetic energy interrogation stimulus from a portion of skin as the applicator traverses the portion of skin and to control the at least one treatment composition component to selectively deposit the treatment composition to the deposit location on the portion of skin based on one or more inputs indicative of a decrease in reflection of electromagnetic energy interrogation stimulus from the portion of skin at the deposit location, wherein the discontinuity identification component is configured to measure a baseline reflectance as the applicator traverses the portion of skin that does not include the region of interest, wherein, as the applicator is moved from being over the portion of skin that does not include the region of interest to being over the first edge of the region of interest and then being over the region of interest and then to a second edge of the region of interest, the reflectance level transitions from the baseline reflectance level to a decreasing reflectance level, reaches a lower reflectance level, transitions from the lower reflectance level to an increasing reflectance level, then to the baseline reflectance, wherein the discontinuity identification component is configured to identify the decreasing reflectance level indicating an increase in absorption of the electromagnetic energy interrogation stimulus from the portion of skin at a deposit location, to deposit the treatment composition in response to identifying the decrease in the reflectance level from the baseline reflectance and to stop depositing the treatment composition in response to identifying the increase in the reflectance level from the lowest reflectance level.