You now have major metallic debris in that motor from the edge of the head and the valve spring debris
I would take the motor out of the car and disassembled it completely and clean every where you can like when assembling the motor the first time, cut the oil filter apart and inspect the oil pump thoroughly for damage from the metal debris washed down into the oil pan already
BTW, are any of the lifters damaged or are you referring to the valve spring retainer and rocker arm damage?