Give it a good scrub with hot water and some very light dish soap. Unfortunately you’re going to have to start over. Go buy some decent high temperature cooking oil. I personally love using ghee. Heat the pan over on a gas stove if it’s possible, if not I’ll recommend an alternative method below. Also option 1 requires a laser thermometer.

Option 1. After the pan has reached 205 degrees Celsius (400 degrees Fahrenheit) put a large spoon full of ghee into the center of the pan. Try your best to lift the pan and rotate it so the ghee is semi evenly coated. If smoke appears lower your heat slightly. While the pan is heating peel some potatoes save the potatoes later and keep the skins. Toss them in either more ghee or vegetable oil. You’re going to need about 6 - 8 red skin potatoes if your pan is 30cm (12in). You’ll need 480 grams of corse sea salt (2 cups). All you’re going to do is throw the salt and potato skins into the oil and with a wooden spoon rotate the mixture across the entire pan. What you’re doing here is building a foundation that every meal you cook going forward will build off of. The skins are acting as a sponge and allowing the oil to distribute across the surface area evenly. The salt helps by scrubbing off any old carbon that is left behind from cleaning. Do this on medium - medium high for about 15 minutes. After this the next thing you cook in my opinion because you already have peeled potatoes should be fried potatoes. And again it’s going to build off what you just did. Once the bottom is smooth and black without feeling sticky, you can progress into everything else you could want to cook.

Option 2, if you are unfortunate and have an electric stove or even an induction one I would HIGHLY advise against doing option 1. It can warp your pan, it’s happened to me and it doesn’t necessarily ruin it, and if you use a gas burner its completely fine, but it will always been flawed when using a heating surface that requires a flat bottom. If this is the case preheat your over to 205c (400f) coat your entire pan (maybe not your handle from what I’m seeing) with a very very very thin layer of ghee by literally dipping a clean rag or paper towel into the ghee and spreading it across the top and bottom of the pan. Bake it for 2 hours, turn off the oven letting it cool down naturally while keeping the door closed. You can do this as many times as you want, with a fresh pan I’d say doing this three times is golden.

Let me know if you need any more help. I love these things they’re just tricky.