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 difficulty breathing, blue or grey lips, chest pain with collapse, a seizure, or inability to wake the child.
These are not usual features of obesity, but they can signal a serious medical problem.
Stay with them and contact emergency or crisis services in your area.
Seek prompt medical advice for a new limp, persistent hip or knee pain, repeated vomiting, marked dehydration, or a child who is unusually sleepy or confused.
Urgent mental health support is needed if a child talks about suicide, self-harm, or not wanting to live.
Arrange a routine appointment if you are concerned about a child's growth pattern, rapid weight gain, eating behaviour, sleep, mobility, or emotional well-being.
Assessment is also appropriate for persistent snoring, daytime sleepiness, darkened neck skin, irregular periods, frequent thirst or urination, or weight gain after starting a medicine.
Every sign above is quoted from the sofidex article on Obesity in children. If you are not sure, err upward — it is always reasonable to be checked.