If I do an upper lip lift, does that mean the lower lip will stretch upward to close mouth and so the chin will become longer?

Thank you for your question. The direct lift removes tissue directly from the upper lip line border creating a slightly raised effect.The corner lip lift is often used to create a more uniform lip line post procedure.  I suggest that you consult with a board certified facial plastic surgeon.
Best wishes,

Lip lifts are an artistic endeavor.  There are no appropriate standard measurements that one should use. The key is to alter the amount of light coming from around the mouth.  We can certainly shorten your chin and raise your lip.  We often do both together.  However, you would not expect a problem closing your mouth and, in fact, your lower lip can't really stretch up anyway.I have a few videos here that may help.

Upper lip lift only affects the upper lip and the space between the upper lip and nose. If done sub nasal bullhorn sometimes can give a rabbit appearance. I prefer the vermillion lip lift which is more accurate. have done plenty of these over the last 25 years. The only way to shorten the lower lip to the chin a complicated oral surgery procedure must be done to remove some bone .