发丝凌乱有你看不见的悲伤
[fā sī líng luàn yŏu nĭ kàn bù jiàn de bēi shāng]
'Tousled hair hides the sorrow unseen to you'. People use it to indicate their sadness that others fail to recognize. The tousled hair here adds on some sense of disorderly emotion to be shown.