messed up sparkplug,do i need a rebuild??

[juanishio]

i dont want to make this long so here it goes....i was on the freeway ,i was traying to cut down some traffic so i floored it,when suddenly my car started loosing power sounding like a wrx...i got home took out the spark plugs ,turns out that the 4th cylinder had a damaged plug.did a compresion test results were 150 150 150 70...cars still runnin weak is there a way a valve could have hit the sparkplug,or is that something just the piston could have done???my car is an s14 with a s13 sr