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 severe chest pain, fainting, severe breathing difficulty, or signs of a serious allergic reaction such as swelling of the face or throat.
If a child or pet chews, swallows, or applies a nicotine product, contact emergency services or a poison information service immediately.
Seek urgent advice for repeated vomiting, marked dizziness or weakness, a fast or irregular heartbeat, or a severe skin reaction.
Do not wait for symptoms.
For routine follow-up, contact your healthcare team if cravings remain difficult, side effects are not settling, or you are unsure how to reduce or stop NRT.
Product changes often solve irritation or practical problems.
Every sign above is quoted from the sofidex article on Nicotine replacement therapy. If you are not sure, err upward — it is always reasonable to be checked.