What's wrong:
* "On your ear" is a bit informal and doesn't sound natural in this context.
* "Is it correct grammar" is a bit clunky. It's better to ask a complete question.
Here are some better ways to phrase the question:
* What are you wearing on your ears? (This is the most natural and grammatically correct way to ask.)
* What kind of earrings are you wearing? (This is more specific and assumes you're wearing earrings.)
* Do you have anything on your ears? (This is a more general question.)
Let me know if you'd like me to help you with any other grammar questions!