Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Seek emergency help for trouble breathing, rapidly increasing tongue or throat swelling, fainting that does not improve, uncontrolled bleeding, or signs of a severe allergic reaction such as widespread hives with facial swelling.
Arrange prompt medical assessment for increasing pain, warmth, swelling, or redness; thick yellow or green drainage; fever; red streaks; or jewellery becoming embedded.
Ear cartilage that becomes very painful, swollen, or misshapen also needs prompt attention.
Ask for routine advice if irritation is not settling, the jewellery is moving toward the surface, or you are unsure whether healing is progressing normally.
The article also says
Contact a dentist for a chipped tooth, ongoing gum irritation, or oral jewellery that repeatedly strikes your teeth.
Every sign above is quoted from the sofidex article on Piercings. If you are not sure, err upward — it is always reasonable to be checked.