Removing & Re-adding library to Itunes without losing anything important?

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I figured out how to batch embed all my mp3s with whatever artwork .jpg I have inside their album's folders with mp3tag

So now all the mp3s in my Itunes folder are embedded with art, but they don't show up . All new mp3s' I have added since do show the artwork now though, since I've been embedding them before I add them.

It's obvious I have to remove & re-add the rest of my library again to get all artwork to show. My question is what is the best way to do this without losing any of my playlists I spent an insane amount of time creating or any other important info?

Thanks