What happens to the Screen Recording not saved to camera roll?

I was using screen recording and stopped recording at about 10-12 minutes, but the video saved to camera roll notification didn’t pop up as usual.so, the video didn’t save. Therefore i searched for the reason online and checked my phone storage as well as cloud storage and even the latest software update but everything was fine. 80gb of Phone storage and 75gb of icloud storage still available and software update was updated to the latest. But later ,the screen recording more than 20 min got saved. So is there any possible way to retrive those unsaved video or is there any internal memories where the video get saved even after not saving to photos.How can i get my videos back?