Google Play keyword rank drop suddenly

Hi, just join this forum
because don’t know where to get answer…

So, I just lost my keyword rank position on Playstore, my app rank at 2nd place for a month, until a few days ago I update it and give a little change to the title and app description, then suddenly my keyword rank dropped from 2nd to 46th place, i think I’ve made a ‘blunder’ update,
now my app not visible to the users anymore, it decrease download and revenue significantly :frowning:
I’ve tried to change it back (title and description) just like before my last update, but it doesn’t help to bring back my rank position

Do you ever experience this thing?
Any idea about this?

Maybe Google Play has changed his algorithm on rankings.