I'm a 20 year old male and I'm developing deep laugh / smile lines around my mouth.

Dermal fillers can definitely improve the appearance of deep laugh lines by restoring midface volume.  It's important not to over-inject those lines directly as it might create unattractive folds around the mouth.  Since it is a very dynamic area, fillers injected into naso-labial folds and lines will not have the same longevity as in other areas of the face. 

Some men develop deep lines around their mouth and depressed cheeks at an early age (perhaps an extreme example is Steve Buscemi).  Since there is no photo, I am not certain this is what you are referring to, but in any case, any volume deficit can be treated with Restylane, Radiesse, and/or Voluma, with a very natural replenishment in skilled hands. male faces are shaped differently from female, and it is important to see a board-certified dermatologist with considerable experience and an understanding of the subtleties.All the best to you! Dr. Clark