weird - is that a blistered decal? looks a bit bubbly.
it think there was some galling in your seat tube (with the seat post). My LBS has this drill attachment. It's got all these little stiff wire brushes that would kind of clean that up. It's kind of like a burnishing tool, maybe. A quick google search didn't find it for me. But I would think a quick touch up with a DREMEL wire brush or something similar would smooth things up for you.
https://en.wikipedia.org/wiki/Galling