Love a Zombie thing and how appropriate for October.
Im thinking:
Drink some Bluish Kool Aid. Remember, your DEAD and that tongue shouldnt be bright PINK. I see this alot in small Zombie films. Make that tongue nice and dark. Nasty blue.
Contacts would make it perfect; I know they are expensive and uncomfortable, but damn it that would look good.
Moisture. Not sure how the Latex would handle it but a little mist would go a long way. Give it that fleshy, moist, undead type feel.