While hezek re'iyah is clearly an established halachic concept, they don't seem to explicate what's included in such a violation. In Bava Basra, they discuss what one may or may not do in building a house due to hezek re'iyah, and it seems that beis din may force a person to rebuild in order to fix any existing privacy violations.
There's also a story in Taanis about a bochur spying on a rabbi's daughter through a hole in their fence (didn't end well for the daughter), but it's aggadah and doesn't discuss the assessment of damages due to voyeurism.
It would seem (though I cannot point to an exact source) that hezek re'iyah would be treated as any other form of hezek and would be subjected to the same forms of recompensation. Much like pulling off a woman's headcovering in public and other forms of damage (see all over bava kama), you only pay what's applicable to your situation.
For public embarrassment to a woman, you pay a very high amount of boshet, but no nezek, shevet, tzar, or ripui. See Bava Kama 8:6. Also in that perek (first mishna) - embarrassing someone who is currently unaware of their embarrassment (like a sleeping person) is just as assur. This is even stated explicitly by boshet (so don't go doodling on your passed out drunken friend's face...). This means that despite the fact that the women originally had NO IDEA they were being subjected to voyeurism, they are still considered to have been damaged and can collect after being informed of their damage.
In this case, they are certainly eligible to boshet (psychological damages). If the injured parties required therapy, they may be able to collect ripui and/or shevet (if the pursuit of damages, embarrassment, and psychological harm prevented them engaging in normal work). Both tzar and nezek refer to physical damage, so neither of those would apply in this case.