Yes, WHIPLASH is a Scrabble word!

Letter values in Scrabble US: W 4, H 4, I 1, P 3, L 1, A 1, S 1, H 4.

Is it a valid word?

WHIPLASH is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

an injury to the neck (the cervical vertebrae) resulting from rapid acceleration or deceleration (as in an automobile accident)
a quick blow delivered with a whip or whiplike object

Also: whiplash injury.