That piston is ruined, Camerart, but it should still run for a while, in a fashion. I don't think those scores will be the only, or even the main, reason for it failing to start.
The score seems to line up with the upper ring locating peg, so there's a good chance someone installed the top ring badly then turned it over a few times. After that it either settled into place, or was torn down again to fix the problem.
Also, something unlovely has happened to the end of the gudgeon pin bore, and the circlip is missing. Do not run it without both circlips correctly installed, or it will ruin the bore beyond repair.
