Localized scleroderma (LoS) or morphea is a rare group of inflammatory disorders resulting in excessive collagen deposition and subsequent sclerosis of the skin and subdermal tissues. Linear scleroderma (LiS) or linear morphea is the most common subtype of LoS in children and primarily affects the face and extremities. This case report details the three-year follow-up of a five-year-old girl with LiS of the left upper lip and adjacent oral mucosal tissue. She also presented with a concurrent developmental root defect of the permanent maxillary left central incisor. Intralesional corticosteroids were considered as a first-line treatment; however, parents declined it. Decision was made to biopsy when the lesion showed signs of progression. At subsequent reviews, the affected mucosal surface appeared to have stabilized but progressive notching of the upper lip was noted. In the long term, after cessation of disease activity, the patient will require aesthetic intervention to surgically correct her upper lip.