嚇到鼻哥窿都冇肉 literally means 'Scared to the point of even nostrils have no flesh'
I was wondering what 'nostrils have no flesh' have to do with fear, so I did some search and found the following article:
舊時廣東人在感受到極度驚嚇時多會說這句話。究竟這與「鼻孔有沒有肉」何干呢?人在此時,反應就是廣東人所講的「嚇到震晒」(身體顫抖不已);誇張點說,就連鼻這部位都會抖震。鼻震動,鼻孔內的毛隨之而震動,所以「嚇到鼻哥窿『都冇肉』」原來指「嚇到鼻哥窿『啲毛喐』」,難怪人們聽後不明所以了。
It said 都冇肉 /dou1 mou5 juk6/ (have no flesh) was a mispronunciation of 啲毛喐 /di1 mou4 juk1/ (the hair move)
Now, I am wondering, What is the logic behind this idea.