Fancy gallery import wrong Xml

Hello (sorry for my terrible english)

I make a huge mistake, i export one gallery (of 10) and import this one gallery.
This operation merge all my galleries to have only one (the one i import).

There is a solution to undo this huge mistake ?
It's possible to fing the old "xml" with all my galleries on my ftp backup and restore the website ?

It's the fancy gallery on wordpress.

Really big thanks