over one's head需要跟in over one's head区分开来，in over one's head在美国俚语里的意思是“处于不妙的境地却无法摆脱”，类似于陷入困境，带着身不由已的些许意味。

He tried to stop，but he was in over his head.

他想金盆洗手，却又身不由己。