My boyfriend always jokes about my shortcomings in appearance when there are many people.

There is a saying called "love me, love my dog". If he loves you, he shouldn't dislike your shortcomings in appearance. Make it clear to him that you hate it when he jokes about your shortcomings in appearance when there are many people, so you will be angry. Tell him that it is impolite to make fun of others' shortcomings in front of them. Warn him, if he doesn't listen, you tell him that you are not without faults, and I respect you, so I won't say it in front of others. If you don't listen, don't blame me for being rude. But I think if he didn't mean it, he would change.