How can I change the shape of my lips but not volume? (Photos)

Lip shape can be improved with fillers. There always has to be more volume when adding fillers, that what they do. A natural look is all dependant on the person injecting you...that is your most important decision. Lip injections don't have to look done or obvious. This is due to the skill of the injector. Silk is a nice lip enhancer, it doesn't augment too much.

There are essentially 2 ways to inject lips for enhancement:1) add volume, or 2) add structureBy injecting small amount of filler along the edges (or border) of you lips, you can create a nice frame to your lips.  This technique gives them better shape without adding much volume.  Alternatively, you can inject more filler into the body of the lip, which will create the increased volume look you mentioned.  To get the result you are looking for, have good communication with your injector.  The result you want is probably the most popular request I get and can be achieved through good injecting technique.I recommend finding a plastic surgeon who is very experienced in lip injections.  A good injector can give you improved shape to your lips without adding volume.  It's all about the technique used.