SOLVED. Adult Sci-Fi. Man is warned not to enter a cave on a planet for fear of death. He's forced? to enter & something lands on his head. Read before 1973. [s]

[Daniel]

I read this book back in high school, so before 1973.
It's set on a planet where a man is warned not to enter a cave, all who have suffer a horrible death. The natives say, "If a Foo sh*ts, wear it." They fear the cave and don't go near it. The man enters anyway (I think he was forced to, possibly by treasure hunters?) and something drops a 'deposit' on his head. Having seen others die painfully, he doesn't dare wipe it off and a symbiote, within, enters his mind. Finding it can communicate with him, he names it 'Pard'.
Pard grants him immortality and he travels the galaxy becoming rich. As time goes by they become more pressed to 'cover their tracks'.

My thanks to any or all who try to help.

[Sue]

This sounds very much like The Healer by F Paul Wilson, though I think it was published a bit later than you remember.

[Daniel]

F. Paul Wilson
Yes, Sue, it was Healer, thank you! Though the cover you offer isn't the one I now recall. The one I remembered after searching the title you provided was of Dalt, with a streak of gray in his hair (from Pard's 'entrance' through his skull) and hand raised, behind a person he was trying to help. Found one on Google search, but unsure how to post it.
Again, thank you.

[Sue]

Was it this one?

I read it on Kindle so I don’t remember the cover.