There are many techniques and "styles" when it comes to lip injections. It is important to discuss with your injector what look you are going for. Bring pictures from magazines or the web. Be sure the injector is very experienced. The philtrum can actually be enhanced with dermal filler if that is desired. Even the choice of filler can make a difference in outcome in my opinion. Those that are more stiff will have more of a tendency to "take over" the shape of the lip and, especially if a little too much is used, the lip can have that "sausage" appearance. Those that are the softest (Restylane Silk or Belotero) tend to preserve the natural shape more but make the size larger.
Lisa Vuich, MD