Yes, WRINKLING is a Scrabble word!

Letter values in Scrabble US: W 4, R 1, I 1, N 1, K 5, L 1, I 1, N 1, G 2.

Is it a valid word?

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

gather or contract into wrinkles or folds; pucker
make wrinkles or creases on a smooth surface; make a pressed, folded or wrinkled line in
make wrinkled or creased
become wrinkled or crumpled or creased

Also: scrunch up.