Large congenial melanocytic nevus (LCMN) on the head and face can have negative psychological effects on children and possibly also parents. Patients and their families experience prolonged periods of stress during tissue expansion treatment. The purpose of this study was to evaluate the psychological impact of LCMN on children and parents and explore their fluctuations of psychological status during treatment. Psychosocial status was evaluated in 30 children with LCMN on the head and face and a control group of 56 sex- and age-matched children using the Child Behavior Checklist and the inventory of Subjective Life Quality for Child and Adolescents. The parents of both groups were also evaluated using the Symptom Checklist-90, the Hospital Anxiety and Depression Scale, and the Perceived Stress Scale. Psychological assessments were performed before expander implantation, before lesion resection, and after operation. Results indicated that children with LCMN were more prone to social problems, withdrawal, and aggressive behavior. Furthermore, their psychological problems increased after entering to school. Parents of children with LCMN had high levels of emotional problems and stress. Continuous expansion resulted in the psychosocial status of both children and parents to reach the worst levels during the period before lesion resection. Six months after surgery, most of these psychosocial effects reduced to levels lower than before surgery. Additionally, we identified several risk factors, namely sex, number of operations, being in education, employment status of mother, and family pressures. Large congenial melanocytic nevus on head and face have considerable psychological impact on children and their parents throughout the tissue expansion treatment. This study demonstrates the need for appropriate psychological screening and interventions.