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 urgent or emergency care after discharge for worsening breathing, noisy breathing, fainting, confusion, blue or gray lips, coughing up pink or bloody fluid, severe chest pain, new vision loss, or signs of a deep digestive-tract injury.
And for anyone, someone who:
Follow-up depends on the exposure and the organs affected.
Someone treated for a significant inhalation injury may need review of breathing symptoms and, in some cases, lung-function testing.
Persistent cough, wheezing, chest tightness, reduced exercise tolerance, or shortness of breath should be discussed with a clinician.
Eye injuries require follow-up as directed by an ophthalmologist, even if pain improves.
Some complications can develop after the initial injury.
Skin burns may need wound or burn-clinic care.
Follow-up may be needed to check for delayed narrowing of the esophagus.
Routine follow-up is appropriate when symptoms are stable but have not fully resolved, when a specialist requested reassessment, or when documentation is needed for a workplace exposure.
Workers should follow occupational-health guidance before returning to a job involving ammonia.
The article also says
After swallowing ammonia, report new or worsening pain, fever, vomiting, trouble swallowing, or the sensation that food is sticking.
Every sign above is quoted from the sofidex article on Ammonia poisoning. If you are not sure, err upward — it is always reasonable to be checked.