Consult your paediatrician for direct examination

Physical assessment is mandatory

Greetings Common causes for a localized dark spot in children include minor trauma, post-inflammatory hyperpigmentation, or a benign labial melanotic macule. In rare instances, multiple mucosal spots can be linked to systemic genetic conditions such as Peutz-Jeghers syndrome. A pediatrician or dermatologist needs to physically examine the spot to rule out atypical lesions or underlying health concerns.

Visit physically to nearby pediatrician.

A physical evaluation or atleast a picture would be needed to give proper consultation.