Today, I started the bleaching treatments that my dentist recommended. Now, my two front teeth have ultra white spots, the rest of my teeth are still yellow and the roof of my mouth is burned. FML
I'm with you #5. Use a dilute H2O2 rinse too. That's the active ingredient in over the counter whiteners anyways. Yields a healthy white instead of that bleached look. Dentist grade whiteners are going to give you spots on the first couple runs, OP. Sounds like you have a sensitive mouth. Do some independent research and go old fashion.
I'm surprised they gave you a home kit, tbh. I used to work at a dentist office's office years ago, and they never recommended a person do teeth bleaching themselves. Most of the home kits either don't work or can cause (like you said) random white spots that are hard to get rid of. In worse case scenarios, you can damage your teeth or gums from using the product incorrectly or for too long.
Most dentists make personal whitening kits for patients to take home now. I don't know what kind of office you've worked for, but every dentist I've worked for has done this. They even take molds and make personalized whitening trays.
My dentist recommended an over-the-counter whitening kit, because professional whitening would work too well and make my natural teeth stand out from all my fillings.