The subject's palm will be cleansed with gauze. Then the microneedle pretreatment versus sham microneedle pretreatment will be performed. This will consist of rolling the microneedles or sham microneedles into the skin for several seconds on the sides of the palm that have respectively been randomized to the microneedle or control treatment. Sham microneedles will consist of a flat roller without the presence of the microneedles. The microneedles are solid and are long enough to penetrate the stratum corneum and enter the epidermis. Microneedles that are less than 700 micrometers in length have been shown to induce minimal pain, and our ongoing work with microneedles that were 650 micrometers in length was rated a 1 out of 10 on a visual analog pain scale. For this study, subjects will rate pain on a visual analog scale after the microneedle pretreatment as well.