that looks to me like a missing scale. actually... from your picture... it looks exactly like a missing scale. I have seen this happen in babies where when they shed... for some reason something does not work right and a scale just comes off. To me... that just looks like skin that is covering an area that a scale should be. It has also recently happened to a scale on my baby male eastern milk's head.

I was helping a friend from the shows sex his baby amel checkereds... and happened to notice one with that EXACT scale completely missing yesterday. No scar tissue... just skin where a scale was supposed to be. I am not sure if it will grow back or not!