It is possible that the card would be declared "spoilt" and given a zero score.
In a freindly club or inter-club match the scorer(s) may just remove the 4 best scores (by agreement) or declare the card "void" and let you shoot a replacement card with some sort of penalty to discourage others from spoiling a bad card just to get the chance to shoot an improved one the next time - the problem being setting a precident by permiting the card to be shot again without a penalty.
In the MPL ( a very freindly competition) we would simply remove the highest scores and count only the lowest ones.