do (one) a mischief
To do something that harms one. Primarily heard in UK, Australia. You sure did your brother a mischief by including him in that dangerous game.
do someone (or yourself) a mischief
injure someone or yourself. informalˌdo somebody/yourself a ˈmischief
(British English, informal or humorous) hurt somebody/yourself: You could do yourself a mischief wearing such tight trousers!