cut (one's) own throat

To cause problems for oneself with one's own actions (which are often motivated by anger). I know you're mad at your dad, but don't cut your own throat here—running away is only going to make your life harder. Tom accounts for nearly 75% of his branch's quarterly sales. So, as much as he annoys you, you'd cut your own throat if you fired him, sir. Look, you cut your own throat when you react so defensively. It makes the media think you have something to hide.

cut your own throat

bring about your own downfall by your actions.

cut your own ˈthroat

do something that is likely to harm you, especially when you are angry and trying to harm somebody else: You cut your own throat when you told him to leave. How are you going to manage alone?