Well, I used this script, it is far from optimal and takes a bit of guessing to know what block you need to start at (not sure how to translate a block number to a timestamp).

Obviously, there are some improvements needed. I am still fairly new at working with Steem.

from piston.steem import Steem

steem = Steem()
search = "@blueorgy/to-upvote-yourself-or-not-to-upvote-yourself-when-why-and-if-its-a-good-idea"
for c in steem.stream_comments(start=3361525):
    if c.identifier == search:
        print("title: " + c.title)
        print("post body: \n")
        print(c.body)
        break
    else:
        print("...")

Also I am very carious about when exactly posts are saved to blockchain. Just after I will click "Post"? I can edit post, but not forever (someone told me, that this is a matter of first payout). Do you have any knowledge about how this works?

Every time you click Post or Update Post the results are stored in the blockchain.