Cylinder wall scratch, need suggestions

[pbsun]

I believe this was done when I was installing the pistons, what do you guys think? Go back to the machine shop?

Also, I can feel with fingernail. Thanks.

[DesertBMW]

those are overheating scratches, I built an M20 that has same scratches like that and it still runs like new. No other way of getting rid of them, the cylinder would have to be overhoned 1mm and you would have to use oversize pistons.