In case of a medication error, the first step to take should be:

In the event of a medication error, notifying the nurse or supervisor immediately is crucial because they have the authority and expertise to assess the situation. Timely communication allows for a proper response to the error, which may include monitoring the resident for any adverse effects, determining if corrective action is required, or providing additional care to ensure the resident's safety. Immediate notification helps in documenting the incident accurately and implementing any necessary interventions to mitigate harm. This step is vital in maintaining a safe environment for residents and upholding the standards of care in healthcare settings.

The other options suggest actions that can compromise patient safety and the integrity of the healthcare facility's policies. Simply documenting the error and moving on does not address the immediate needs of the patient, while informing only the resident might lead to confusion or panic without proper guidance from medical personnel. Correcting the error without informing anyone also poses risks, as it prevents the healthcare team from taking necessary steps to ensure the resident's well-being.