You won't want to give them back if you could. You won't have a full tooth if you put a crown on it. It's just a post. It'll will look like you have a mouth full of tic tacs. You may want to try to get used to them for a while and see how you feel in a few months.
You should be able to go back to him to correct it as you adjust to your bite. I've had a lot of dental work. As a patient, I've never had my bite correct right after i left because my mouth was still numb. I think I have the best dentist in Las Vegas because he was the one that let me know these things and that I should come back. Did you have crowns done on your front teeth? I have veneers on my fronts and crowns on my back teeth.