Malabsorption during teens/puberty can arrest overall
growth—height, frame, body structure, gonadal
development etc. Hence, a person may have less prominent frame—including facial frame.
However, if a small frame runs in families, then this can also be a contributing factor. Another possibility is vitamin D deficiency, or a bone disease. It would be best if you could get a doctor to examine you and see whether you need investigations. Take care!