Relapse means a person who stopped using has started again. Like asthma or diabetes, addiction is a chronic condition that can flare, and a return to use tells you something about what the treatment plan was missing. It is information, not a verdict on your character or your loved one's worth. What you do in the next day or two matters more than the relapse itself, so reach out for support quickly and treat this as a moment to adjust care, not to give up.