I agree that it sure does look like the same thing as the cory in the photo I uploaded, and that one does have lymphocystis.
Yes... that's good to seperate him for a bit. Maybe it won't be passed on to your other fish. I think it gets a foothold when there are water quality issues or any other reason or issues that might compromise a fish's immune system. A slight injury, scrape, or such, too, might invite infection by the virus.
So maybe excellent hygiene, i.e., pristine water conditions, may help prevent other fish from contracting it, if it is in your tank.