It is understandable to notice meaningful facial changes between ages 16 and 20. Late adolescence is a period of ongoing maturation: the jaw, chin, nose, cheeks, facial fat, skin, and muscle contours can all change gradually. Weight fluctuation, orthodontic treatment, stress, sleep, acne, medications, hairstyle, and differences in photographs or lighting can also make the face appear dramatically different. Masseter Botox only relaxes the chewing muscles. It can modestly narrow the lower face when enlarged masseter muscles are the main cause of facial width, but it does not alter the jawbone, chin projection, cheek volume, or overall facial growth. If you did not notice improvement, your facial change may not be primarily due to masseter muscle bulk, or the dose and treatment plan may not have been appropriate for your anatomy. I would avoid repeated Botox solely to chase facial changes while your features are still maturing. Comparing standardized photos taken several months apart—same angle, lighting, expression, and body weight—can provide a more accurate sense of change. If you have jaw pain, clicking, bite changes, one-sided enlargement, difficulty chewing, new headaches, or rapidly progressive asymmetry, schedule an evaluation with your dentist, orthodontist, or primary care clinician. A facial plastic surgeon or dermatologist can also assess whether any cosmetic treatment is appropriate after an in-person examination.