I believe PV means HitPoints. He's probably portuguese or spanish speaker.
Like Jayjay said, Shoy, you should create a Global or Instance Variable (which in fact would be a Constant), called MAX_PV, and set it to 100.
When you're adding PVs because of time, add a condition, before adding, which checks if PV <= MAX_PV and only add PVs if current value is lower than MAX_PV.
When receiving the bonus for killing do not compare against MAX_PV, so you can add beyond that value.