I am guessing this was photoshop'd, it isn't very fluent, you can tell the arm has been smudged / Liquified
Infact, The model looks pasted onto that background
looks like there should be more hair than is showing e.g. the flick on the (her left) side seems to stop suddenly unlike natural hair
and as said ^
The volume on her left is just far too thick,
She should have showed a little emotion in her face instead of looking bored, it doesn't do much for her Jaw line, I personally would have pushed her head up a bit and told her to open her eyes WIDE instead of looking like she is about to go sleep.