There’s a trepidation at the end about stepping out of a comfort zone and revealing something that may not be perfectly polished. Your poem is both daring and well structured. The last line stood out to me and tied the emotional reasoning behind the metaphor together for me.

I love the rhythm and tone. And some of the phrases knock me out; I especially like The hammers pound my temples out: / my brain’s construction zone.
It really shows the fear most people have of stepping out of the box, of taking a risk, and I can’t say I haven’t experienced this feeling before. But I know, Mr Fish, that you have already climbed that ladder, else you wouldn’t be as respected a writer here as you are!