How to recover my Apple Music Library after changing regions?

The text in my last post didn't show 😭

I'm linked to my mom's family sharing and I wanted to get a game that was available in Japan so I switched my region to Japan and switched it back. Then I looked at apple music and saw my music was gone, I already know its because I changed my region but I don't know how to fix it.

[Re-Titled by Moderator]