Well, not to worry about it anymore as Facebook frequently trying to bring us new changes and updates to make more user friendly interface, Few days before Facebook added a new feature "Facebook allows its users to edit their comment rather than deleting and rewriting them" So, now you have a option that all your comments are editable or you can say re-writable.
How to edit your comments on facebook :
This option is for all comments.
Step 1: First, go to your comment page as like below :
When you are done with your editing just press Enter and you are done.
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