As a subject, how can you add commas? Personally, I think the following sentence is more reasonable:
Yes (there used to be)
nobody
know
this
hemorrhagic
until
I
think
about
wound
scar over
about
my
If you make a slight change in your sentence, it should be:
while
I
think
about
wound
scar over
about
my
that
someone
have
known
this
It's bleeding.
This sentence is consistent with what you want to express.