Weird Problem with rigging

Hi there,
I recently started rigging on blender 2.79 but I’m getting weird problem like this one.
https://imgur.com/a/tHQ1Nb5
Can anyone please tell me how to fix this issue.

Looks like your weight painting. Can you put in a blend?

well, here’s my blend.
https://drive.google.com/open?id=1hn2IwrKkVdAx3yb1zkOGomGBubAURYH0

Clear your parent on the hair mesh and reparent it to the bone-head is the quck fix.