think i created a glitch when mirroring an arm - fixable or do it over? (noob)

I have been making a figure for practice, had everything done except i needed to make a copy of the arm, flip it around and put it on the other side. I haven’t done that before, and somewhere in the confusion of the shift-d, ctrl-m, y - no didn’t work undo - redo, i confused blender and it made a ghost copy of the arm i can’t get rid of. It only exists in object mode, it disappears in edit mode. I have another version of the file, but it’s a fairly large step back from where i had gotten to (praise the gods that past grief taught me to always save 2 versions and shuffle between them so i still have one if the other breaks).
So is there a way to delete the ghost arm or do i have to scrap the file and redo a bunch of stuff?

Does it have a mirror modifier on it?

press alt h in editmode to make sure you didn’t accidently hide the mesh

!! yes i did accidentally hide it. Didn’t know about that function. Too much looking at the screen while tapping keys.
Thanks a bunch.