Will your cheek really sink in after tooth extractions?

They can: Cheeks can lose their support from teeth if they're lost.

It is possible: The presence and/or absence of teeth can definitely have an influence on the support of the lips and lower facial third. An individual who has all of his or her teeth removed without replacement can and will likely have the appearance of loss of fullness of the cheek and lips.

Not really: Extractions without tooth replacement is usually what can lead to changes in facial appearance. This can be due to teeth shifting positions or "bite collapse" (where you chin is closer to your nose when you close your mouth, also known as a" loss of vertical dimension" in the mouth) this can be prevented with timely replacement of the missing teeth before damage is done.