cut one's own throat
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.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
cut one’s own throat
tv. to do something that harms oneself. He’s just cutting his own throat, and he knows it.
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.