Is there a way to undo changes in iTunes Library

No, sorry, there is no "undo" function for such changes. Whether re-importing all your tracks would correctly label things I don't know, but other than manually going in and getting things back where they were (note that you can group-edit tracks, such as for an entire album), that's your only option unless there's a Windows app that can make such changes easier. There used to be at least one such for Macs, but I don't know if anything like that still exists for Windows. The one I found on a quick search (iHomeServer) is discontinued. Perhaps someone else here can make a recommendation

Regards.

While there is no official undo support if you've been using iTunes for long enough the corrupted information may be sitting in an older version of your library in the Previous iTunes Libraries folder inside your iTunes folder. If you have .itl files in that location see my script ExportImport. Temporarily rename the media folder so the library cannot read the current wrong values from the tags, connect to the .itl that has the information you want to recover, export it, restore the name of the media folder and reconnect to the current database. Import the exported data.

tt2

BTW, changes made in iTunes are normally written directly to the file tags, but if you don't have the Keep media folder organized option selected then the files could retain their original names and folder locations, which may still reflect previous metadata. Another script, TagFromFilename, can attempt to pull details from the file path into the library where that would be useful.

tt2