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 trouble breathing, swelling of the face or throat, collapse, unresponsiveness, a seizure, or other signs of a severe allergic reaction.
Emergency help is also appropriate if your child is in immediate danger of harming themselves or someone else.
Seek prompt medical advice if your child develops worsening pain, marked injection-site swelling, persistent vomiting, unusual sleepiness, or symptoms that concern you after the visit.
For routine advice, contact the clinic if you have questions about results, referrals, vaccine reactions, growth, development, learning, behaviour, or emotional well-being.
Also call if expected results do not arrive within the timeframe the clinic gave you.
Every sign above is quoted from the sofidex article on Well-child visits. If you are not sure, err upward — it is always reasonable to be checked.