Edited TIFF and DNG files are not visible
I've been working on some RAW images in Lightroom Classic version 13.1 using MAC OS. My workflow has been to crop and tweak highlights, shadows, vibrance, saturation and that kind of thing before, if neccessary, using either Lightroom's De Noise feature or a plug in De Noise application. These create either a DNG file or a TIFF file. Once completed I add a flag to the image so I can easily filter the selected images for viewing.
Today, while part way through an edit Lightroom crashed. When I re opened the application the original Lightroom edits are still there as RAW files but the DNG and TIFF files are not showing in the filmstrip at the bottom or in the library view.
The edited DNG and TIFF files are still in my folder on the disk and I can open them in Photoshop or other applications. If I try to re-import them into Lightroom it says there already in the library.
Can anyone help as to how I can get these images back into view in my Library and Editing views please?