This summer a single chick hatched. At three days, it got pecked on the head. That put an end to any future it might have. I euthanized it by scissoring off its head. It's terribly upsetting when this happens to a small chick, but I don't see how your little chick can recover.
I fell last spring and hit my head hard. Still remember the terrible pain. Being human and able to help myself by taking ibuprofen was a blessing.
Animals suffer and have no way to understand any of it. They comprehend nothing about why they are suffering, how to help themselves, nor that there may be an eventual end to the misery.
Last spring I made the heartwrenching decision to have our older dog euthanized. I have never regretted my decision to help him escape the misery that he would face as his cancer got worse.
Please consider euthanizing your little chick if it is unlikely that the suffering will result in a successful recovery!