I like the way this is written (it's a little short imo, but I mean short doesn't mean bad, and I have a tendency to ramble)
If it were me (and I'm by no means an authority, http://fanaticalreflection.tumblr.com/ is a little bit of my stuff, but mostly older things) I would elaborate more on the mask especially. What is the mask for? What's being masked?
I personally am a sucker for alliteration, so a suggestion if you wanted some of that would be to rewrite the part about the song of death so it follows the door of death
(i.e. The door of death was drummed upon, and a loved one had answered. Not at all a major flaw, but if you wanted to add more rhetoric, that'd be a way to do it)
I feel like the word "waiting" in the end could be replaced with "longing" for better emotional effect.
For years she waited; / decades turned to centuries / longing, longing for that peace / that comes with eternal rest
That's just the stuff noticed off the bat. Overall it's very well written and I think it has a good shot at your contest. Best of luck :D
EDIT: Edited spacing on my points