What did Nehemiah do to some of the Jewish men who had married foreign women?

Answer: Beat them and pulled out their hair

Nehemiah rebuked and cursed them, beat some and pulled out their hair, then made them swear by God not to intermarry.

“I rebuked them and called down curses on them. I beat some of these men and pulled out their hair. Then I made them take an oath before God and said, “You must not give your daughters in marriage to their sons or take their daughters as wives for your sons or for yourselves!”— Nehemiah 13:25 (BSB)