Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
These are generally routine or same-day concerns rather than emergencies.
Use glucagon as trained and call emergency services if your child with suspected low glucose has a seizure, becomes unconscious, cannot safely swallow, or does not recover as expected.
Call emergency services for trouble breathing, swelling of the face or throat, or a widespread allergic reaction.
Contact the diabetes team promptly for repeated high or low readings, frequent painful injections, new skin lumps, insulin leaking often, uncertainty about a dose, or difficulty giving injections.
Seek urgent advice if your child is vomiting, has moderate or high ketones, cannot keep fluids down, or has glucose that remains high despite the prescribed correction plan.
Get urgent help after a major insulin dosing error or suspected overdose, even if your child initially seems well.
The article also says
Follow the child’s sick-day and ketone plan.
Every sign above is quoted from the sofidex article on Giving insulin shots to a child. If you are not sure, err upward — it is always reasonable to be checked.