I understand that your battery usage is not showing up on your iPhone. I'm happy to provide some help for this issue.
If you haven't already, please force close the Settings app and restart your iPhone as iOS clears cached data and does other system optimizations when you turn your device off and on.
If you're still having this issue, your next step is to reinstall iOS on your device; this will help us isolate the situation further. Reinstalling iOS should not affect any of your data, but it is always a best practice to make sure you have a current backup in either iTunes or iCloud.
Use the “Update” option and not “Restore” and these steps will reinstall iOS. Keep in mind that these steps were written for a different issue, but they will still help us isolate the situation further.
Thanks for using the Apple Support Communities. Cheers!