Trismus, a distressing complication characterized by restricted mouth opening, frequently occurs in head and neck cancer survivors following treatment. This case report examines the combined efficacy of OraStretch, a therapeutic device targeting jaw mobility, and Continuous Passive Motion (CPM) therapy, specifically the “Contract Relax Antagonist Contract" (CRAC) protocol, in preventing trismus. The study presents findings from patients who underwent head and neck cancer treatment and participated in a rehabilitation program incorporating OraStretch and CRAC therapy. Results reveal a notable enhancement in mouth opening range and functional outcomes post-intervention. Additionally, patient-reported improvements in quality-of-life metrics highlight the significance of this combined approach. These findings suggest that integrating OraStretch with CRAC therapy holds promise as an effective strategy for mitigating trismus and improving functional outcomes in head and neck cancer survivors.