Oops, it doesn't look like 'demasking day' is a national day..

Other days

lisp

Lisp Day
prosecco

Prosecco Day
mean girls

Mean Girls Day
kiss a brunette

Kiss A Brunette Day
bow tie

Bow Tie Day
cuddle up

Cuddle Up Day
latina equal pay

Latina Equal Pay Day
youth

Youth Day
healing

Healing Day
slime

Slime Day