Since you don't have sagging (laxity) or wrinkles, these lines to the sides of the mouth are usually from the nose to the mouth (nasolabial fold) or the mouth to the chin (mesolabial or marionette), are best treated with a filller like Juvederm or Restylane.  Both would work well.  On average maintenance for this in your age range would be about twice a year.  Also see my in depth article on Mouth and Lip issues which may also be helpful.    Dr. I