Student or Learner
There were the first wounds, but the sharpest and deepest pain of all was yet to come.
What does it mean?
Bhaisahab's paraphrase is right on the money. I would just like to point out that "yet" means "still" in your sentence.
As well, the word "yet" can also be a conjunction that shows contrast in the same that "but" does; using "yet" instead of "but" adds some emphasis. So we use "yet" as an adverb and as a conjunction.