Understanding the difference between lip contouring and traditional lip liner. Below, a makeup pro shares advice on understanding the difference between lip contouring and lip lining, as well as tips for mastering each. Lip Contouring vs. In other words, if lip liner is about precision, lip contouring is about illusion. Unlike traditional lip liner, lip contouring is typically created with softer, more blendable products designed to diffuse rather than sharply define.