If you accidentally delete a file on your personal computer, no worry - just look in the Trash Can, find the file in question, and recover the file. Just do this before you empty the Trash Can.
Comments, published on our blogs, cannot be recovered once deleted.
I deleted a comment - but now realise that I acted in haste. How do I recover the comment that I deleted?To this person, there is no useful answer.
Whether you moderate comments before or after they are published - and whether you moderate using the dashboard Comments wizard, or your email Inbox - once you click on "Delete" (and possibly hit "Yes"), the comments in question are gone. There is no Trash Can for deleted comments.
Some blog owners will retrieve the deleted content (possibly, from email), and manually re publish the content, when possible. Unfortunately, that will produce a comment with (possibly) the deleted text - but no link to the originator of the comment deleted. If the text content of the comment is the relevant detail to you, as the blog owner, you may do this - but the republished comment won't be the same.
Delete comments with care. Once you delete a comment, you won't get it back.