Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services for facial drooping accompanied by signs that could indicate a stroke, including:
Emergency assessment is also appropriate for seizures, marked drowsiness, widespread weakness, or a rapidly spreading blistering rash in someone with a severely weakened immune system.
Arrange urgent, same-day medical assessment for new one-sided facial weakness, especially with ear pain or blisters.
Treatment may be most useful when started early, and other causes must be considered.
Seek urgent eye care if you cannot close the eye fully or develop eye pain, increasing redness, light sensitivity, or blurred vision.
Routine follow-up is important if facial movement is not improving, pain continues after the rash heals, or hearing and balance problems interfere with daily life.
These symptoms are not usually emergencies, but they may need specialist support.
Every sign above is quoted from the sofidex article on RHS. If you are not sure, err upward — it is always reasonable to be checked.