Baby of the dawn

[RiverNotch]

On reading the title, the first thing that popped into my head was "Lemonhope" (which, incidentally, shares pretty much the same subject). But anyway....

"Baby of the Dawn"

Young soul, pure soul, baby of the dawn,
locked inside your head, locked behind your door,
forgive your mommy and your daddy for your crying storm. 

In line with an earlier comment, maybe just
"...
locked behind your door,
forgive us..."?
Locked behind your door doesn't necessarily imply locked inside your head, but it could still evoke it, especially if enhanced by the late stanzas....*

Young soul, pure soul, baby of the dawn,
no one knows that you bear inside you a little baby thorn. Way too long. "no one knows your bear a thorn / inside you" says the same thing, but with more the point of brevity.
Let it feed, let it grow, let it bleed
and soon enough you will be able to leave. I think this could either be more vivid, or be replaced with something else. Maybe this and the lines before and after could be used to elaborate on the nature of the thorn, as well as the nature of the crime?
A home has never been a place for the obscene, 
it's not your home when it's a crime scene. Rhyme sounds kinda off. I think this line should be enough; omit the earlier. And maybe make the crime itself clearer; what exactly did mommy and daddy do? You don't have to say it directly, but the references so far aren't enough.

Old soul, wise soul, baby once born in dawn, Naw, "baby of the dawn" is enough here. Even if there's an element of growth here, "baby of the dawn" is better in terms of that color-punch of maturity.
you lit the skies as you crawled your way outside that door. Bit long again. Could be pared down -- and maybe made into an imperative? Set the mood in the first, elaborate in the second, lead to an uplifting, but a still-to-be-done, coda, maybe.

In general, each line could be shorter, and the images could be more vivid, as well as better elaborated on. Thanks for the read!