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 for new or worsening breathing difficulty, blue-gray skin or lips, fainting, confusion, severe pain, repeated vomiting, reduced urination, vision changes, or trouble swallowing.
And for anyone, someone who:
After eye exposure, obtain prompt reassessment if pain, redness, light sensitivity, or blurred vision continues after rinsing.
Arrange routine follow-up if a rash persists, skin remains painful, coughing continues, or there are ongoing headaches, fatigue, swallowing problems, or work-related symptoms.
An occupational health clinician can help assess workplace controls and whether temporary changes in duties are needed.
Digestive burns, significant lung exposure, abnormal blood tests, or methemoglobinemia may require scheduled follow-up with the appropriate specialist.
The article also says
Follow the poison specialist’s or clinician’s instructions even if symptoms improve.
A minor exposure that has been fully rinsed and causes no ongoing symptoms may need only home observation, but this decision should be based on the product and circumstances.
To reduce another exposure, keep dye in its original labeled container, follow ventilation instructions, use the protective equipment listed on the label or safety data sheet, and store products away from food and children.
Never transfer dye into a cup, bottle, or food container.
Every sign above is quoted from the sofidex article on Cloth dye poisoning. If you are not sure, err upward — it is always reasonable to be checked.