Babies teeth not straight/grinning

Me

My son (11 months) keeps grinning his teeth a lot (and loud). We try to say no but he just won’t listen. Now one of his upper tooth is missing a piece where he keeps grinning on it and the lower teeth became crooked and not straight (with space in between - they were closed at first) from too much grinning.

Is there a way to stop it and is it ok?

Could it be bad for his teeth or just bad for appearance?