Yes, TOMENTA is a Scrabble word!

Letter values in Scrabble US: T 1, O 1, M 3, E 1, N 1, T 1, A 1.

Is it a valid word?

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

filamentous hairlike growth on a plant
a network of tiny blood vessels between the cerebral surface of the pia mater and the cerebral cortex

Also: tomentum cerebri.