Lamotrigine, a widely used antiepileptic and mood stabilizer, is associated with a risk of dermatologic hypersensitivity reactions, which can range from mild rashes to severe cutaneous adverse reactions. We report the case of a 27-year-old female with recurrent depressive disorder who developed widespread rash and facial swelling following initiation of Lamonex SR (lamotrigine) 100 mg once daily without titration. Prompt recognition and discontinuation of the drug led to complete resolution of symptoms. This case highlights the importance of careful titration and early monitoring when initiating lamotrigine.