I’ve run out of regenerations, so how do you find the Untempered Schism?

So regenerations work by drinking an elixir of life, that is how you get 12 regenerations.

The Untempered Schism only gives regenerations to people who have at least 1 regeneration remaining.

The way to obtain an Untempered Schism is to craft it.

(if this is wrong, please correct me, but to my knowledge, this is all correct)

Nothing wrong, you're totally correct :)