You should be able to find out if it’s damaged using the DSPOBJD command.
To recover you can either restore the object from a save made before the object was damaged or you can use CPYF to take a copy of your data, delete the damaged object and rename the copied file. If you have logicals, then you’ll have to delete them and restore them after you’ve renamed your data file. You should also check to see whether your file is journalled or has triggers or restraints, these you will have to re-apply manually.
Or you may be able to just run the CHGPF command against the damaged physical file, referencing the source member for the file (presuming its definition was from DDS). This has worked for me before. Apparently, if the definition portion of the object is where it’s damaged, running the CHGPF command rebuilds it (and its logicals, if there are any).