You haven't mentioned which type of device you're using Lr mobile on. I'm not familiar with Android phones, but if you're using an iOS device such as an iPhone or iPad then the original photos should still be stored in the 'Camera Roll' (Apple's Photo app). I suggest you reopen Lightroom mobile and tap on the 'Camera Roll' button as shown below. Hopefully, your photos are still stored there.
Thank you for your reply. I took the pictures on my iphone using Lightroom Moblie in .dng format. As far as I can tell the pictures were never in my camera roll unless I converted them and saved them there. There were three I had saved from Lighttroom Mobile to my camera roll, and those are still in the camera roll. The rest that were .dng and only in Lightroom app appear to be gone.