Stop deleting comments on Facebook just because of typos; the company is rolling out Comment Editing and Edit History.
Comment Editing will give you an easy way to edit your comments at any time whether you have replied previously to your own status or other user’s status updates. The feature seems very much inspired from Google +; though a year ago, Facebook allowed editing comments within a few seconds of posting them so you could fix immediately recognized typos.
While Edit History will keep the all different versions of the comment and anyone who can see the comment can see what was changed by clicking on the Edited link.
The new update has been made available for most of the users, but still if you miss the changes, have patience! The update will be rolled out globally in next couple of days. To learn more about comment editing, visit facebook.com/help/?faq=105443102880679.