reimport playlists from usb stick

Hello guys!

I've got a library exported on my usb drive. yesterday, i've accidentally removed about 500 tracks from my collection tab. these tracks were also saved in several playlists (at once). i've still got these playlists on my usb drive AND stored on my internal drive - is there a way to reimport the playlists from the usb drive with all data present like "last added on", because i'm sorting my playlists based on this while playing.