I’m another one who says you don’t need to take it down to metal.
What I do in that case is heat the pan in my oven as it’s coming up to temp (500F) - take it out at around 300F.
Then I get about 1/4 teaspoon vegetable shortening, wipe that all over the inside with a paper towel, then back in the oven for an hour or so, shut it off, let it cool down, then do that a couple of more times and it patches the “hole” fine - and then I make sure I cook a bunch of high-fat stuff in it for a few days, and it’s good as new.
Seasoning cast iron - it’s another one of those things that seems to be controversial, though it shouldn’t be. Everyone has their way of doing it, and it’s the only right way and every other way is wrong, but it really comes down to heat, fat, and time. If you just keep cooking fatty stuff in it, it’ll heal up on its own eventually.