Can headphones dent your head?can it change your head shape and affect your head skull?

If tight will squeeze soft tissue and leave temporary reversible indentation, but there will be no permanent "dent", and no change in skull affecting head "shape".

Positional skull deformities can occur in infants due to prolonged pressure, but not likely in an adolescent or adult. An head phones should not be so snug as to exert significant pressure.