I put my cast iron skillet on the stove top , turned up the heat slowly then turning it up high , when I removed the pan, I obseverd a ring/mark the size of my glass top burner almost like a burn mark on the bottom of the pan, ( the pan was larger then the burner ) It was unable to remove the stain/ mark with steel wool . How can I restore it ?
One of three things happened :
If the spot is black, and the rest of the pan is kinda brown-ish: You fully cured the seasoning on the pan, so you need to bake the pan to get the seasoning full cured.
If the spot is dull and brown, while the rest of the pan is black or near-black: You just baked the seasoning off of your pan. You'll need to strip any rust, and reseason it.
You have enameled cast iron, the spot is brown or black, and the rest of the pan is some other bright color.
For the first two, see What's the best way to season a cast iron skillet?
For the third one, just be thankful that you didn't heat the pan enough to soften the enamel and have it fuse to the stove. But even then, you're shortened the life of the enamel. You just have to deal with the new look, and expect to get some crazing if you heated the iron so it expanded past what the enamel could stretch.
In general, I'd advise against heating cast iron on high. Not only can it ruin the pan's seasoning, but because it holds so much more heat than a thinner pan, the temperature won't drop nearly as quickly when you put food in ... making it way more likely that you'll burn your food.
Although it's possible to flip food in cast iron after you're built up the right muscles, the typical person is going to wear out if you try the 'keep flipping your food until the pan's cooled down enough' technique if you're doing it with a cast iron skillet.
(yes, I've done the second one ... and my brother fused a le creuset pot to the stove when he went to boil water and forgot about)