Can I undo a change made in gallery?

[Ebunn]

While viewing photos of ppl, gallery asked me "who" and I attached a name. Then I noticed many photos that were NOT that person, showed up under that name. I chose a 'wrong' photo & there was an option to delete tht name from it. (I thot) After I hit delete, when I went back to my main photo search page, I noticed that where all the contacts/names with all their own photo folders suddenly went from about 65 contacts to only **TWO!** Why did all the other contacts & their face recognition photos disappear?!? More importantly, is there any way to revert that change. I did immediately check on the cloud & fortunately that change had not happened there yet, so I immed turned off th sinc.
Can ANYONE PLEASE HELP me fix this?? Thank you!

 

[B. Diddy]

Are you using the Google Photos app or the stock Gallery app?