- Why did everyone start to hate the Russians if the U.S. did the same thing in Afghanistan, Iraq?
- What needs to be corrected in the management of Russia first?
- Why did Blaise Pascal become a religious man at the end of his life?
- How do I know if a guy likes you?
- When they say "one generation", how many do they mean?
In your sentence, this is an introductory word, so it will probably be hyphenated (and yes, separated by commas). You can also write without a hyphen, but only when “by” is a separate preposition. Example from Google:”They were walking along a visible stretch of road.”
In this sentence, everything is initially so bad that the hyphen can not be corrected. If you put (only) it, it will contain punctuation errors. If you don't put it – lexical and semantic information.