The nothing powerup is because if the players health is already 3 then i dont want it to pass that so I just made it do nothing.
One hand fair, on the other, I feel like you could have easily done something like this
Powerup():
If Health >= 3:
Health = 3
Elif Health != 3: (or) Health <= 2 (or even) Health == 2 or Health == 1:
Health = Health + 1
I don't know Unity's coding language so this may not work if you just copied and pasted it in but I feel like something like this would work out for you, and if that doesn't work I would suggest making it give points when the player is at full health.