Temporary hit points and Pw: your maximum goes above its normal bounds for some time, before returning to normal. If your normal maximum changes for some reason, the temporary maximum changes by the same amount. There are two proposals for how the effect should end:

• The entire effect is timed, and once it ends the temporary buffer vanishes. If your HP would go below 1 as a result of this, you could either die or have it set to 1, depending on implementation.
• The temporary buffer drains away at the rate of 1 point per turn, and the effect naturally ends once it’s gone.