I just give a shot here for very direct translations. A lot of expressions in the poem are very private and ambiguous. Also, 身から出た錆び is an idiom which means, like, you reap what you sow(or there are many other English translations for this idiom), but here it is directly translated in order to give a better picture of the words. Any help from a native English speaker would be appreciated.
I have crunched the rust that came off of my body
My heart gets tinted with the hue as if being added afterwards
Only by means of borrowing others’ standards (or All I could do was to borrow others’ evaluation standards)
If I could complete even the outer moat, the inner shape might be seen
(The third line is very hard to understand. I can't tell whether the sentence is modifying the sentence before or after. The sentence is basically a fragment.)