Restoring deleted music or videos depends on whether your phone's operating system offers that functionality. Lark Player does not have the capability to perform this action. Please check if your phone supports file recovery features.
If you only want to not see the certain files/songs in Lark Player, you can choose "Hidden Files/Songs", and the steps are below:
Go to the "Settings" page → Tap "Hidden Songs" in the center of the "Settings" page.
If you hide a song, that song will not appear in the playlist.