The revenge visited upon her family will be inadequate.
There's always a way if there's commitment enough. Strip them, put them in a dark cold moldy room, strapped to a table so they can't move, keep using various torturing techniques while intermittently using healing magic (especially on their mind), keep doing that for how many years Liz had been living with that family, along the way at various points; stab a burning stick through their eyes and gouge them out, tear out there tongues, tear out their teeth, crush their jaws, burn their fingers and toes(bonus if you can heal and repeat..), peel the skin and nails off their fingers and toes, burn their throats, scalp them, rip off their ears, draw out their intestines and drown them in a vat of excrement, rip off their extremities, rip off their limbs, rip the rest of their skin off(these latter preferably at the end part of the ordeal). AMONG various things, if you have several years to work with surely you can come up with a whole bunch of various fun things.
And, if that world happens to have Irukandji jellyfish, throw in a few buckets of that too..

...Oh well, perhaps you're right and it's still inadequate? Any suggestions?