Background <p>Nostril overexposure is a common aesthetic concern among Asian populations, which significantly affects facial harmony. Traditional surgical interventions carry risks such as substantial trauma and visible scarring. This study aims to evaluate the clinical efficacy of Botulinum Toxin Type A (BoNT-A) injections in treating nostril overexposure using three-dimensional (3D) scanning technology.</p> Methods <p>This study recruited 52 patients seeking improvement for nostril overexposure. BoNT-A was injected into the nasal dilator muscles. Changes in nostril cross-sectional area and alar mobility were quantified using 3D scanning technology before treatment and at 4, 12, and 24&#xa0;weeks post-treatment. Subjective improvements were evaluated by patients and one independent plastic surgery experts using the Global Aesthetic Improvement Scale (GAIS).</p> Results <p>A total of 32 patients completed the entire 24-week follow-up period. Post-treatment 3D analysis showed a significant reduction in both nostril cross-sectional area and alar mobility. At 4&#xa0;weeks post-injection, the nostril area decreased from 89.42 ± 13.21 to 72.50 ± 13.93&#xa0;mm² (<i>p </i>&lt; 0.05), and alar mobility decreased from 10.50 ± 3.92 to 4.64 ± 3.09% (<i>p </i>&lt; 0.05). GAIS scores indicated that both patients and expert rated the improvement as significant at 4&#xa0;weeks. Measurements at 24&#xa0;weeks approached baseline levels.</p> Conclusion <p>BoNT-A injections effectively and safely improve nostril overexposure with high patient satisfaction.</p> Level of Evidence IV <p>This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors <a href="http://www.springer.com/00266">www.springer.com/00266</a>.</p>