Crushed Valve Stem

I got a 76’ cj5 with the 304 in it. I heard a ticking sound coming from passenger side valve cover so I decided to pull the rocker arms. Turns out the top of my driver side valve stem (closest one to the radiator) has been mushroomed over/ crushed down and pitted. The other ones look great. No bent push rods or anything. What would cause this? Should I be worried or just replace the valve?

 

Welcome to the forum. I'll move this to the top. To answer your question, possibly lack of lubrication, the rockers are lubricated from the lifter the lifter, up the push rod through a small hole in the rocker arm and dribbles down over the valve stem. A restriction or deflection of oil that doesn't reach the valve stem along with it being an exhaust valve. Run it with that valve cover off and see if it is getting enough oil. Unfortunately the head will have to come off.

 

Pics will help. If you're talking about the end of the valve, there are some reasons for the failure. Ron