It is likely that you’re referring to a horizontal skin crease on the nose bridge area.
This is actually a skin crease from childhood due to frequent “pushing” of the nose upwards. This is often done by the child with a very sensitive nose , who might have sinus allergies and the common early morning runny nose and sneezing. This is also known as the “salute sign” , when the child uses the hand and finger to push the nostrils upwards. This causes the horizontal skin crease on the nose.