Is it one of these three areas?
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The blue you circled.
When it was stated in the spoilers that there was a tattoo above King's eye, logically I was looking for it in the raws. Your attention is automatically directed to the last panel and my initial thought was that that just looked like a smudge, a blood spatter or just a shadow. I was rather disappointed.
Though, when I read the raws again I noticed that there's actually much clearer image on the previous page, but it's a real 'blink-and-you-miss-it' panel. It's not a panel where you would look at for a lengthy amount of time when reading the chapter and you kind of blurt out the detail. But when you do see it, you can't unsee it again and then it also becomes clear where it is in the last panel.
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Pretty sure the majority of the people who keep saying that it's just some fragment of King's goggles, either missed this panel or refuse to admit that they might be wrong.