Any good ideas on how to implement a one time reward system?

So I have if statements that represent your level for example

if (xp >= 100) { display.text = " Level 5 Novice"; }

I need it to show up at the end of the match if it adds up past the level for the first time and save that you have received it, also if you happen to level up twice have it give you both? Any good ways for this?
(could also completely scratch my level display system doesn’t matter I just did it this way since it works)

Thanks <33

If you only look at the player’s xp. It’s easy to do it as a high score. Use highXP to see if the player has passed it.