one day i realized a few of my valves were tapping pretty loud. so being the stingy person that i am, i decided to adjust the valves myself instead of paying someone. so i get all of the valves adjusted just fine and i get to my last valve. i get to the far left exhaust valve, i tighten it to proper specs and begin to tighten the lock nut, but it wont stay tight to 10ft lbs and i realize im stripping the adjust screw. so every time i tighten the lock nut, the valve lash gets loose again! so am i screwed?

P.S. it a d16a6 engine

-Danny