The damned will be in hell suffering forever. Does it follow that their overall sufferings will be infinite? I will argue in the negative. (I am not claiming that the suffering sin hell are finite, just that infinity of suffering does not follow from everlastingness.)
Argument 1: Suppose that the amount of suffering decreases exponentially to zero as time goes on. Then, it seems, the total suffering (the integral of momentary suffering) is finite, even though the suffering goes on forever.
This argument has some weaknesses. One of them is that total suffering is not just the sum of momentary sufferings. Such phenomena as boredom, dread of the future and hopelessness also have to be factored in.
Argument 2: What determines how much total suffering one has gone through is not the objective length of time that the sufferings have taken, but the subjective length of time. If one had a painful operation that in fact lasted an hour, but neurological manipulation made that hour seem subjectively like ten seconds, then one really had only ten seconds' worth of suffering. Now imagine that the internal clock of one of the damned is continually slowed down. During her first year of objective time in hell, she undergoes a year's subjective time of suffering. During her second year of objective time in hell, she undergoes half a year's worth subjective time of suffering. During her third objective year, she has a quarter of a year's worth of suffering. And so on. Even though she suffers for eternity, her total subjective time of suffering is two years. So, assuming that the intensity of her sufferings doesn't go up with time, her total suffering is finite.
An oddity about this scenario. If her future is subjectively finite, does that mean that her life feels like it is cut short early? But in fact she objectively lives forever. This is weird.