As Frank pointed out in his comment you cannot retract close votes after the question has been closed however you can vote to reopen the question if you think it it is on-topic now and has the potential to attract good answers.
Especially when closing as too broad or primarily opinion based, one of the main reasons for closing a question is to get the asker (or someone else in the community) to edit it so it's on-topic again.
Also some "bad" (downvoted) questions have excellent answers so if you think this particular question is a candidate for that go ahead and nominate it for reopening.