Q: Missing music in storage management screen. How do I get it back?

Hi Kawierz,

Welcome to the Apple Support Communities! I'm sorry to hear you are having this issue with your iPhone. If you have accidentally deleted your music from the Manage Storage screen, you should be able to sync your music back to your iPhone the next time you connect to iTunes, as outlined in the following article:

Sync your iPhone, iPad, or iPod touch with iTunes using USB - Apple Support

Note: On the other hand, if you are using Apple Music, the music storage reporting may not display as you are expecting:

On an iPhone, iPad, or iPod touch, if you don't make music available for offline use, it's cached using the space available on the device. The device will remove cache, and the cached music, as space is needed by the device.

Delete music, movies, apps, and other content from your iPhone, iPad, or iPod touch - Apple Support

Cheers