caned until blood

I think "appeared" would be more natural. If you insist on a passive form, it's a toss-up between your two suggestions. I don't care for either, but can't think of anything better.

appeared works for me. Thanks, Avangi.

Revisiting this, my subconscious gave me, "until the blood came." (too simple!) "The" is required in this most natural version.

Ummm. It's not simple to me. In fact, it sounds alien to me in this context.
Thanks, anyway.

I understand your concern. I believe the sense of it is that in vulnerable situations where injury is possible, blood is not far from our minds. Hence "the blood." In your versions, it seemed as if blood was something of a surprise, rather than a common, if not expected, measure of severity. The arrival of the blood is a signal. (it came) Surely a lugubrious subject.

That's interesting. I'll keep that in mind. I may not use it for now but when I get used to it, I may.