What do you mean exactly by "put MusicBee back on" (what type of install)? Where were your playlists stored previously, and was it the same type of MusicBee install (Installer, Store, Portable) of MusicBee?
Do a search of ALL drives using Windows File Explorer (system settings set to "show hidden files and folders") for a folder named "Playlists", and/or any files with extension *.mbp (MusicBee-proprietary playlists) or common playlist extensions like *.m3u/.m3u8 if you may have used those instead.