Lexicon makes backups here: Backups and how to restore them
So there may be something to restore, keep an eye on their date created.
As for why it happened; if you import it will overwrite existing tracks so if you made changes in Lexicon and then overwrite from a DJ app, then the data from the DJ apps will come in again and overwrite what you had in Lexicon.
If you want to import and prevent the above from happening, you can use the Specific Fields option and only import the fields that you want, the rest won’t be overwritten.