me too...i used red on everything but did i manage to skip that thinking it didn't need it....? damn.
the other possible damage you may have is the piston skirts can get squeezed out of shape from the piston hitting the valves.
I've had them shear before so now I try to get the cam manufacturer to provide two holes in the cam for two dowel pins. I purchased a box of hardened dowel pins and double pin all my cams in "high performance" applications. Hard part is finding the timing chain gear with two holes.