I would recommend backing up your device to iTunes or iCloud and doing a recovery mode reset. This will remove the software and then readd it on there this will fix any glitches that may have occurred during your iSO update.
Do keep in mind if you are updating your device via Wi-Fi and it is not a good connection this can cause the update to pause/resume and this can cause issues with the iSO update going threw successfully.
You can use this article for guidance!
If you can't update or restore your iPhone, iPad, or iPod touch - Apple Support