Inadequate treatment or neglect of odontogenic infections can have serious consequences. The potential for spreading through fascial planes and intracranially can cause compromise of the airway and cavernous sinus thrombosis respectively. On rare occasions this can lead to a rapidly progressing necrotising fasciitis, with destruction of soft tissue, making reconstruction difficult. Antibiotic administration without removal of the cause is inadequate and can complicate subsequent management. We report the presentation and successful management of a 13-year-old boy, who developed necrotising fasciitis in the submandibular region as a result of inadequate initial treatment of a carious, lower molar resulting in significant skin and soft tissue loss.