Help identifying possible damage

I'm trying to identify what kind of damage might exist on this Griswold #6 skillet - I apologize in advance for the picture quality. This skillet appeared to be in pretty good shape when I got it, although after a half-day in the E-tank, most of the crud was removed, and I noticed this scaling. It's rough to the touch, and covers most of the cooking surface and side wall. I thought that this might be heat damage, but the bottom of the skillet is fine. I have an older Lodge #8 that has obvious heat damage and flaking, but the entire skillet is covered with it. I thought that perhaps the pan had shorted out to the anode in the tank and thus started to corrode the pan, but I think I ruled that out. The pan sits completely flat and doesn't have a wobble, which also leads me to rule out heat damage - but, I'm new to this, and I'm at a loss.

So, any thoughts from the experts?

Interestingly enough, the pan appears to be taking the seasoning. The picture you see is how the pan looks after 5 seasonings with Crisco.

I'm not really concerned about the collectability of the pan, since most of my pieces are users. I just hope that this skillet is still usable. I love these #6 skillets, since they are the largest size that I can center on all four of my stove burners.

Thanks for all of the help that everyone has been thus far; hopefully, one day, I'll be able to pay it forward.

If the black areas in the photo are raised, and you can see milling marks in the metal in the spaces in between, you just haven't gotten all the crud off yet. Fire damage is red and scaly.

As always, thanks Doug!

I'm not sure if I should stick this back into the E-tank, or try a lye bath. From what I understand, the lye bath won't have any effect on removing the crud if there is no fat\oil left in the carbon.

I did notice that my battery charger was only putting out about 2 amps when cleaning this piece, and on all subsequent pieces. The steel sheets that I was using as anodes were pretty rusted and corroded. Tonight, I replaced them with steel legs from a broken trampoline (which was scheduled to be sent to the recycling center anyway) and not the battery charger is putting out around 7 amps. Perhaps with new anodes, the tank will do a better job at removing the remaining crud.

If you don't want to do the lye bath, oven cleaner and a garbage bag for a few days has worked very well for me.