erubescence

The act of becoming red; reddening.

Redness of the skin or surface of anything; a blushing.

I then ventured to ask the master to ask small and red Dougal what cutlery was; but from the sudden erubescence of his pallid, ill-fed cheek, and the alarming brightness of his eyes, I twigged at once that he didn't himself know what it meant.

Reddishness.