1993 Other Saturn Models 1993 Saturn SL1

I have a 1992 saturn. My timing chain stretched and jumped teeth, and bent all my intake valves and left nice marks on my pistons. Is it expensive, depends on who does the work, I am working on mine and just the timing chain kit was 220. I am replacing the head from a wrecking yard, because new valves are too much, so I need to go through it, and my question follows;

How thick is the top of the piston? My valves left pretty good marks on them, do I need to worry about the damage to the pistons, or can I be reasonably confident on the strength of the piston?