Nesidioblastosis is a rare condition of organic persistent hyperinsulinaemic hypoglycaemia, with fewer than 100 cases since it was first recorded. However, an increasing prevalence suggests previous underdiagnosis due to poor knowledge and awareness. This case describes the presentation, clinical decision-making and unique challenges in diagnosis and care of a 21-year-old female with nesidioblastosis and extensive psychiatric comorbidities. She was repeatedly misdiagnosed until 2021, despite having presented to emergency departments with hypoglycaemic symptoms for over 7 years. Her symptoms were often misattributed to behaviours secondary to restrictive anorexia nervosa and borderline personality disorder. Even after appropriate diagnosis and management, she suffered a complicated post-operative course. Patients with psychiatric comorbidities are at higher risk of distress, communication difficulties and inadequate social support, all of which could be better managed with increased multidisciplinary collaboration between endocrine, surgery, psychiatry, pain management and social work. This study highlights the importance of well-rounded patient care that addresses all facets of patient health. This approach not only improves quality of care, but also reduces overall readmissions, revisions, morbidity and mortality.