This is a relatively straightforward system to implement, so I'm not quite sure how you have set it up, such that it is not working.
For example, how exactly are the scores being displayed, and from where do they obtain the score values? For example, attribute, actor value? Once the score (damage) value is displayed, how is that then added / subtracted from the main score?
Although your description is pretty good, a narrative is a notoriously error-prone way to explain what you want code to do, due to the ambiguity of language! Diagrams / screenshots would help. Also, screenshots of your code could help to identify the problem.