The best thing to do, is to visit an avian vet; the next best is to visit a vet with an interest in avian & exotics, the next is to visit a normal vet.
This link may help you search for avian vets:
Association of Avian Veterinarians
If for whatever reason, the birds cannot be taken to a vet, then assuming that the problem is scaly face mites, ivermectin can be ordered online. You would need to treat both birds as it is easily contagious and it can take a while for symptoms to show after becoming infected. Treating both birds prevents them from repeatedly reinfecting each other. You also need to follow guidelines to disinfect the cage, its accessories and other areas where the birds perch outside the cage.
Of course, the problem may not be mites and for that reason, I would strongly advise you to make a vet appointment.
Regarding your bird's cere - Could it simply be that she was in breeding condition? (when females come into breeding condition, their ceres change to a brown colour and can sometimes also become crusty).
If the shaking is only when waking in the night, it might be a good idea to leave a night light on, near the cage, then it isn't pitch black and disorienting if she wakes.