Teeth Whitening?

I bought the classic teeth whitening strips today and used them only once so far today. My teeth didn't hurt at all and I figured that maybe this time I would be lucky with them, (because I've used them before and they killed me!). Well, not until later this evening did my teeth start feeling sensitive.... Does anyone know of a way I can whiten my teeth without pain, or do you know how to help with the pain i'm experiencing with these strips? Thanks
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Yes, go to a dentist
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