I believe the dentist may have ruined my teeth.?

I recently went to a new dentist because I've relocated to another state since my last dentist exam. The dentist said that I had a significant amount of plaque on the top of my front teeth. I asked him if he meant that they were whiter on the top than the bottom and he said yes. I explained to him that the white on top had appeared the other day after I used a new whitening product in a tanning bed. I umed they were just whiter because I smoke and drink soda and the top of my teeth just wasn't as stained as the rest. I said, "How could plaque happen in an hour?" but he insisted it was plaque and it should be scd off. I had him stop halfway through because it was so painful but now the top of my teeth has an indentation where the enamel was scd off and it's yellowish. They're incredibly sensitive. I don't know what I can do about this. How do I handle the dentist? And is there a way to fix this so my teeth look and feel normal again? I'm afraid my teeth are ruined.