Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
Call emergency services if hoarseness occurs with:
Difficulty breathing or blue or grey lips
Harsh, high-pitched, or noisy breathing
Inability to swallow saliva or new drooling
Rapid swelling of the tongue, lips, face, or throat
These symptoms can mean that the airway is becoming narrowed.
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
Someone who has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Seek same-day medical care if you cough up blood, develop hoarseness after a significant neck injury, or have severe throat pain with fever and trouble swallowing.
3
Does any of this apply?
Book an appointment
Book a routine appointment if hoarseness lasts four weeks.
Arrange an earlier assessment if you have a neck lump, persistent ear or throat pain, painful swallowing, unexplained weight loss, or repeated episodes.
The article also says
You should also seek earlier advice if the change began after neck or chest surgery, after a breathing tube, or if you smoke or previously smoked.
Professional singers, teachers, performers, and others who depend heavily on their voices may benefit from earlier assessment.
Every sign above is quoted from the sofidex article on Hoarseness. If you are not sure, err upward — it is always reasonable to be checked.