Start with safety. If your loved one is in immediate danger, call for help and get them any needed medical care. Their well-being comes before any legal question, and you can move them or arrange supervision if needed.
Then report it. Notify the facility's management, and report to adult protective services or the state agency that oversees care facilities; involve law enforcement if there is a crime or immediate danger. The Long-Term Care Ombudsman program can also help. Reporting triggers investigation and protects other residents.
Finally, document everything. Photograph injuries and conditions with dates, write down what you saw and were told, and keep records. Request your loved one's records. Then a free, confidential review can evaluate whether there is a claim — but safety and reporting come first.