Yes, EFFACEMENT is a Scrabble word!

Letter values in Scrabble US: E 1, F 4, F 4, A 1, C 3, E 1, M 3, E 1, N 1, T 1.

Is it a valid word?

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

shortening of the uterine cervix and thinning of its walls as it is dilated during labor
withdrawing into the background; making yourself inconspicuous

Also: self-effacement.