Accidentally clicked 'Reset to Default' in Camera Raw

If you are editing raw files, Camera Raw stores the edits for each image in an .XMP “sidecar” file with the same filename as the raw file. It’s stored in the same folder as the raw file. You can see them in the folder on the desktop, or in Adobe Bridge if View > Show Hidden Files is enabled. So, if you maintain regular backups, and you restore the XMP files from the backup for all affected images from the most recent backup before the mistake was made, you should be able to bring back the edits as they existed at that backup restore point.

For example, I back up with Apple Time Machine which updates its backup once an hour as long as the backup volume is connected, so in theory I should normally be able to restore Camera Raw edits from as recent as an hour ago.

To restore edits that are in .XMP sidecar files, you do not have to restore any of the raw photo files from the backup, only the much smaller .XMP files. If you added AI masks to an image, there may be an additional .ACR sidecar file containing those, and you should also restore that.

If you were editing DNG, TIFF, or JPEG files, for those formats Camera Raw writes the edits into the image files themselves. For that reason, XMP sidecar files aren’t created for those file types. In that case you do have to restore the actual photo files from the last backup restore point before the mistake was made.