I told my dance teacher that I have a crush on him
Do you think that he feels the same way about you?
I don't think so; asking him out would make me uncomfortable since he's my instructor.
If yo have a crush on your teacher, it would be best to ignore those feelings and try to spend less time thinking about him. While finding authority figures attractive is not abnormal, you should not act on those feelings, it will put both you and your teacher in an awkward spot if you ask him out on a date.
I didn't say I'm going to ask him out. I just said I have a crush on him.
I beg your pardon, it seems I misinterpreted what you had to say.  In your case, then, it's probably fine to let your instructor know that you have a crush on him, but be sure that he understands that you are just being friendly.  He should know that you simply find him attractive, and that you respect him as a teacher.