I like the premise of this. If you just knew what to say. If there was anything that could be said. Or done. To make it all better. What you wouldn't do. Who hasn't felt that way?
There's a few things that should be ironed out though.
"If I could find the words
To mend this all anew
I'd cry out at the top of my lungs
Until my body was black and blue"
This stanza feels especially forced. A few other rhymes and rhythms could be done better, but this one really needs help.
"I would scream them in a second
Oh, the words I would shout!"
This makes me think of Dr. Seuss. It a bad way. It doesn't help the mood of the poem. But maybe that's one's just me.
"To make this blow not sting"
I found this line awkward. I had to reread it a couple times.
I'm guessing that you would want to delete the first 'my'. Aside from that this was another great piece that I've read of yours. Painful and yet so very familiar. I will be checking out more of your writing, as I have really liked what I've read so far.
I hope you get through this.
Please don't make your identity a relationship.
Because I have to give actual writing advice
(typos: 'I scream at the top,' 'I'd scream at the top?)
You use 'scream' very often,
(and sometimes the tense changes,) but you may have wanted that effect: "I would take all this back and never say these things," and then, "I would...(scream them in a second,) past.
Very good part:
"My mind screams for closure
and answers to this pain
reasons for why the world fell apart
and why things aren't the same."