Transparent Target

I can't see it there.
Yet, its mine to bear.  
Be that as it may.  
It marks me in some way.  
So that I'm left out.  
I have no doubt.  
That it's on my forehead.  
Or my back instead.  
Somehow you can tell.  
You see the target well.  
That's why you don't relent.  
Even though I'm spent.  
Where did it originate?  
What was the date?  
If I only knew.  
Maybe I could understand you.