To ward off one danger only to encounter another, often greater, one; to replace one problem with an even worse one.
小明好不容易摆脱了繁重的课业压力，却又被安排了更多的社团活动，真是前门去虎，后门进狼。
Just as Xiao Ming finally got rid of his heavy academic burden, he was assigned even more club activities; it was truly a case of driving out a tiger through the front door only to let a wolf in through the back.
Next Idiom