You can re-season your skillet using an oven or stovetop.
For the oven: Use a cloth to coat the skillet with a thin layer of neutral cooking oil on all surfaces and rub off any excess oil with a fresh cloth. Then, throw it in the oven at 500ºF for one hour.
For the stove: Heat your skillet on your burner over a low to medium heat. Next, use a cloth to coat the skillet with a thin layer of neutral cooking oil on all surfaces and turn the heat to high. Heat the skillet until it starts smoking and leave it over the heat until the pan stops smoking. Your skillet will be hot, so remember to use a mitt (we prefer silicone) when handling it.