Summary: Botulinum toxin-A (BTX-A) is widely used for aesthetic purposes and is recognized for its vasomotor actions. However, new medical applications have emerged. This study aims to describe the effect of BTX-A on human skin perfusion, particularly vessel diameter, blood flow, and blood vessel density in regions with known low vessel density. This case series involved 40 patients who were treated with subcutaneous injections of BTX-A and sodium chloride 0.9% into marked skin areas on their backs. Skin blood flow, vessel diameter, and density were measured using infrared thermography and Doppler ultrasound before the injection and on days 1, 7, and 21 posttreatment. BTX-A-treated areas exhibited higher blood flow, larger blood vessel diameter, increased blood vessel density, and the emergence of new detectable perforators. In contrast, areas receiving sodium chloride 0.9% showed no significant changes. Data analysis was conducted using an independent t test and Jeffreys interval. BTX-A injection appears to boost human skin blood circulation, potentially prompting the emergence of new detectable perforators, gradual widening of vessel diameter, and increased blood flow and temperature. These observations suggest potential benefits of BTX-A in areas with compromised blood supply to stimulate the emergence of new detectable perforators.