I go even a step further.

Taking the code example above (not intended as criticism, only to have some work basis):

Why is it one time health, and then is it HP?
For me there is only one base name, and if I choose health for it, then my other variable would be var vOldHealth.
I would drop newHP completely, as it only reads the entity value one time and is used directly afterwards.
Also I would use a less generic function name, like checkSkinChangeOnHit().