Your lorikeet my have any number of problems. You will need to Find an Avian Vet that can examine your bird in person.
If the bird is kept outside, it could have mites or a disease it contracted from other wild birds. Do NOT treat for mites unless it has been diagnosed and only use what an avian vet prescribes. Here in the USA the over the counter mite medicines often kill birds and the poor birds don't even have mites.
If you have added something new to the bird's diet, it could be an allergy. If you feed fresh fruit, the person growing the fruit may have put a chemical on the crops.
If your house has dry air, you may need to get a humidifier, because dry air will cause birds to get dry skin just like us.