Hello there NiteloxYT,
Thank you for using Apple Support Communities!
I understand that you are having an issue with your screen recording not saving to your camera roll. I am more than happy to help you out with this.
If the screen recording did not save properly there is no way to retrieve it. To prevent this from happening in the future, please be sure that your iOS is up to date to the latest version by going to Settings> General> Software Update.
If the iOS is up to date, I would recommend restarting the device by turning it off and on. If you continue to have issues with screen recording please post back here.
One alternative to this is recording segments and allow each to save to your photos. From their you will be able to share them, import them to a computer, or upload them to iCloud.
I hope this helps! Have a great day!