Most of us have natural asymmetries in our faces. Many people (myself included) have one side of the face that is flatter and broader, and one that is fuller and more narrow. The most common place to observe this asymmetry is in the area of the cheekbones. In my experience, women tend to notice it in themselves more than men, because women tend to notice as they put their blush on, that one side requires a bit more than the other to achieve the same highlighting effect.
Just as you can camouflage asymmetries in the cheeks and lips with makeup, you can also camouflage them in a more semi-permanent way with injectable facial fillers such as Perlane, Juvaderm, or Restylane.
The advantage of the hyaluronic acid facial fillers mentioned above is that they are easy to do, and are not permanent if you DON'T love the results. The disadvantage is that they are not permanent if you DO love the results. The hyaluronic acid fillers last about 5-6 months in the lips and 9-12 months in the cheeks. The more mobile an area is, the quicker the filler is absorbed. The most permanent solution is a custom designed implant.
I would recommend consultation with an experienced injector and/or surgeon. Good luck!