Can persistent emaciation and bone pain for which there is no medical explanation be due to the evil eye?

The evil eye is real and has an effect by Allah's will. Many of the Salaf interpreted the verse: "And indeed, those who disbelieved would almost make you slip with their eyes" as referring to being afflicted by the evil eye. A Muslim should not attribute everything that befalls them to the evil eye or sorcery without proof. Rather, they must seek treatment and consult doctors. The effect of the evil eye can be repelled by lawful ruqyah, prophetic incantations, and supplication.