Background: Forehead contouring can be a component of facial feminization surgery (FFS). Its complications have been rarely reported on and are often described as "hypothetical." Methods: A case report of complications from forehead contouring resulting in frontal osteomyelitis and sinusitis. Results: A female patient presented with frontal osteomyelitis, sinusitis, and forehead contour deformity after a type III forehead contouring surgery. She had failed prior treatment including oral antibiotics, IV antibiotics, revision sinus surgery, and revision nasal surgery. For definitive treatment, she underwent an anterior table resection, sinus obliteration with bony contouring, and pericranial flap. Conclusions: Forehead contouring represents a recent significant advancement in FFS and gender-affirming therapy. Descriptions of complications and their management are important when novel therapies such as FFS are introduced. This case demonstrates complications from type III forehead contouring including osteomyelitis, frontal sinusitis, and forehead deformity.