Ok so here is the rule:
You have inexplicable luck that seems to kick in at just the right moment. You have 3 luck points. Whenever you make an attack roll, an ability check, or a saving throw, you can spend one luck point to roll an additional d20. You can choose to spend one of your luck points after you roll the die, but before the outcome is determined. You choose which of the d20s is used for the attack roll, ability check, or saving throw. [...]
So the rule only states "you can spend one luck point to roll an additional d20", and then says "you can spend one luck point after you roll the die".
So my question is a bit of a two-parter:
- If I don't like the roll I made on my luck die, (Eg. I roll a 10, choose to roll a luck die, then rolled a 5) do I not have to spend the luck point?
- Can I spend more than 1 luck point per roll? Eg. I roll a 10, choose to roll a luck die and rolled a 5 - can I roll another luck die?