Made the mistake of putting cast iron in dishwasher. What do I do now? Is it ruined for good?

5. Re-season Your PanRe-seasoning is essential to restore the non-stick surface and protect it from future rust. Follow these steps to re-season:
1. Preheat your oven to 375°F (190°C).
2. Apply a very thin coat of cooking oil to the entire surface of your cookware, including the exterior and handle.
3. Place the cookware upside down on the middle rack of the oven to promote even seasoning.
4. Put a sheet of aluminum foil or a baking sheet on the bottom rack to catch any drips.
5. Bake the cookware for one hour.