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 if swelling around your neck causes trouble breathing or swallowing.
Seek same-day medical care if the swelling becomes red, hot, very tender, or is accompanied by fever.
These features can suggest infection rather than ordinary fatty tissue.
Severe weakness, fainting, confusion, or repeated vomiting after stopping long-term steroids also requires urgent assessment.
Book a routine appointment if the area is new, getting larger, painful, or affecting movement.
It is also reasonable to make an appointment if you are concerned about its appearance or do not know what caused it.
Arrange a review if you take steroid medicine and notice a new fat pad, especially with easy bruising, muscle weakness, facial rounding, or other body changes.
Keep taking the medicine as prescribed until you receive medical advice.
Every sign above is quoted from the sofidex article on dorsocervical fat pad. If you are not sure, err upward — it is always reasonable to be checked.