to shoot oneself in the foot

• 这叫做弄巧成拙。

  That's what you call shooting yourself in the foot.

• 他们这样做实际上是弄巧成拙，更清楚地暴露了自己。

  By doing that they have really shot themselves in the foot. All they have done is given themselves away even more.

• 我看，你又弄巧成拙了。

  As far as I can tell, you've shot yourself in the foot again.