The eyes naturally get rid of dirt and substances while you sleep. The crust you often find on your eyes and eyelashes when waking up is a result of the eye's self-cleaning process. This could irritate your eye and even potentially scratch the cornea.  Try to ignore any discomfort. Hopefully, the eyelash has disappeared like magic as your eye naturally removed it. If the eyelash hasn't disappeared, it may have moved into a comfortable and more easily accessible area. Then you can remove it using other methods.

TL;DR in Chinese:
带着掉落的睫毛进入梦乡。 夜间不要用手揉眼睛。 第二天醒来的时候检查眼睛。