Did you create a new catalog and import the photos?
Did you select all photos and then click on Reset?
Are the edit steps shown in the History Panel (left side of the screen) in the Develop Module?
Do you have backups of your catalog file from before this happened? (If not, why not?)
Thank you for your questions/advice. The answer for your 1st question is yes, and "may be" to your 2nd question. Fortunately, I had exported the recently developed photos into my external head drive. After reverting back to the original catalog, I have re-imported those developed photos. Now everything is restored. I need to learn more about the subtleties in using the Lightroom.
Re-importing is never a good thing to do.
None of what you said is a good thing to do.
Why are you doing this?