Introduction: The individuals with the Schwartz-Jampel syndrome usually presents a face feature with low-set ears, prominent eyebrows, micrognathia, facial muscles hypertrophy, pursed mouth, and lips. The objective of the study was to evaluate the use of BTX-A in the treatment of facial myotonia related to SJS. Methods:  We offered explanations about the disease and the use of BTX-A in perioral muscles to two patients with this condition that attended our ambulatory care clinic. Case report: Case 01: JSN, female, age 36, was diagnosed  at the first year of life with blepharophimosis, reduced mouth opening, and lips’ protrusion. Case 02: JSS, 18, female, was diagnosed at the first year of life with "shrinking chin", puckering of mouth, blepharophimosis, and valgus genu. Results: Patients were reassessed two weeks after application. The myotonia was no longer detected, facial appearance was better, and mouth opening had increased. Conclusion/discussion: Botulinum toxin should be considered as an alternative treatment when  facial myotomy interferes with self-esteem and functionality (impairing eating and communication). Lack of major adverse events and the relative ease of application indicate that this strategy can be widely used.