"Who the hell is this in front of me
Antagonist of my own story
Blackened with my disgrace
Shadows cover his face"

^This began great, the creativity portrayed in your very first stanza just jumped out at me, and I was immediately intrigued by your poem. I loved how you decided to pick something so creative in your second line. "Antagonist of my own story" That single line was fantastic, phenomonal in my opinion. But it was only a little thing in your poem, I'd love to see you write another poem about this part.

"Who the hell is in this mirror with me
Face like man but dark with pity
These tears they streak my face
An old boy dies away"

^Another strong stanza, describing your reflection. This is actually very overused, but I liked how you described the reflection. Despite still describing tears on your face that many people try to do with this, it seemed more angry than depressing which was an impressive diction. And your last line "An old boy dies away" was intriguing. Pushing the audience to read on to really understand these little hints you've laid out for us.

"Well I know he can not be
Unless I decide to change everything"

^To put this out plainly, I didn't completely get this part. In a sense, I do get what you're saying, but only on the barest of principles, maybe it's just me and the age that I am.

"As I walk around as someone else today
Fake a smile with someone else's face
Realize I'm heading a new way
Live a lie with someone else's name"

^Anyone can relate to this. Faking a smile and this cliche idea, something that really isn't rare at all, a feeling that is actually very common. But then, you were able to speak this simple thought, "I'm really dying inside" with an original concept. And also the cliche "Living a lie" made it original and interesting with the next words "With someone else's name"

"Who the hell is this who is me
The man who's taken all of my tragedies
Demented and ashamed
He looks the other way"

^Wow. I loved the idea of this, a different way of asking yourself who you are by adding "The man" as if he isn't totally you.

"We're all living a lie today
What's your name, scream your name out
We're all living a lie someway
Decide your name, decide your place
We're all living a lie today
What's your name, scream your name out
We're all living a lie someway
Decide your name, decide your place"

^A great repetition, very common in lyrics and songs. In a sense it's very overused in media, but you did a good job with it.

Overall, this was a good poem, not the best but most definitely not the worst. 4/5 Hope to read more from you soon. I recommend working a little more on the flow of your poems.