I burnt my friends pan, how bad is it?

I was using a friends pan, heating oil in it to deep fry something, and I accidentally let it get over 200°C (400°F). I poured all the oil out immediately, but there was a black ring on the teflon wok where the edge of the oil was. Is this a problem? Have I damaged the non stick surface or is it just a greasy... show more I was using a friends pan, heating oil in it to deep fry something, and I accidentally let it get over 200°C (400°F). I poured all the oil out immediately, but there was a black ring on the teflon wok where the edge of the oil was.

Is this a problem? Have I damaged the non stick surface or is it just a greasy residue? How can I fix this?

Extra information: I was just heating the oil, there wasn t anything frying in it when I made the mark. Also, I left the pan with soapy water over night then tried to clean it with more hot soapy water and a rag, no change.
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