Crest - 3D Professional Effects White Strips

Yee-ouch! I got this for a super deal with a rebate, and man, I'm wondering if it was worth it. I had originally intended on posting about these Crest 3D Professional Effects White Strips, but it looks like it's going to have to wait. I tried twice to get these work for me, but about 3 hours after each application, my teeth felt like something was crushing them. It was a nearly electric pain. Someone told me to try using ACT and Sensodyne for a few weeks before trying again. So I shall. So I shall..