【喻】事情干开了头，就不能不干到底（一般指不好的事或有风险的事）。而家经已洗湿个头咯，点收倒手啊？（现在已经干开了，怎么罢得了手？）

describes a situation where a person has already started in doing something and it is not a good idea to turn back or stop half way; literally 'the head is already wet'; to be entangled in a situation that can not be withdrawn easily