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 trouble breathing, loss of consciousness, a seizure, or possible meningitis symptoms such as severe headache with fever, neck stiffness, confusion or unusual sensitivity to light.
Contact the implant or surgical team promptly for increasing pain, redness, swelling, drainage, fever, persistent vomiting, worsening dizziness, new facial weakness or a processor or implant-site problem.
Seek urgent medical assessment for clear watery fluid leaking from the ear or nose, sudden marked facial weakness or severe, rapidly worsening swelling.
Routine questions about processor comfort, sound quality, programming or rehabilitation can usually wait for normal clinic hours.
Every sign above is quoted from the sofidex article on Cochlear implant. If you are not sure, err upward — it is always reasonable to be checked.