Plumpers are popular but traditional irritants aren't suitable for sensitive lips. LipFusion came out with a great solution: Micro Injected Collagen Color Shine. As the name suggests, Lip Fusion uses collagen rather than skin irritants to plump the lips. This is a great moisturizing product too.
I would have to say my favorite lip plumper is the LipFusion clear color. It is a little on the expensive side, but I absolutely love it. I'm not a huge fan of the colored glosses, but REALLY love the clear.