Storing, counting and showing score on object hit?

Okay so I’m making a game which is similar to the assault course missions you can find in Call of Duty. The aim is to just run through the map and shoot targets as fast as possible.

I have a target that when hit by my projectile, it flips down so it goes from facing you to facing the ceiling and being parallel to the floor.

I already have a timer in my game but I’m unsure on how to count score when these targets are hit. I’d like it to count simply as 1,2,3,4,5,6,… and so that they can’t repeatedly shoot the same target for score.

Can anyone help?

I did this for my participle study project, to stop the player hitting the same target

Maybe this can work for you, if you plan to have a online mode this might not be the recommended way