Hello meghann96,
Thank you for using Apple Support Communities! I understand from the information you provided that songs in Apple Music are missing album artwork; I'd like to help.
While the following resource is for help with iCloud Music Library, it provides some relevant troubleshooting steps to try for this issue:
Get help with iCloud Music Library
Specifically, check out the section labeled "If the artwork for some of your albums or songs is missing"
If you still have issues, force close the Music app:
How to force an app to close on your iPhone, iPad, or iPod touch - Apple Support
Then, restart your iPhone:
Restart your iPhone, iPad, or iPod touch - Apple Support
If the issue continues after that, check for, and install, any available updates for your iPhone:
Update your iPhone, iPad, or iPod touch - Apple Support
Hope this helps.
Best Regards.