How do I restore my playlist on Apple Music? Deleted accidentally

There is no "undo" function for a deleted playlist. Your only hope is to restore your iPhone from a backup that might have that playlist. Be aware that restore is an all or nothing process. You cannot only restore playlists (fro example) and any information on your iPhone between now and when the backup was created will be lost after you restore the iPhone.

Restore your iPhone, iPad, or iPod touch from a backup - Apple Support