Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
Call emergency services for severe breathing difficulty, chest pain, fainting, uncontrolled bleeding, or sudden severe abdominal pain.
A painful hernia that becomes firm, cannot be pushed back when it normally can, or occurs with vomiting or skin colour change also requires emergency assessment.
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
Someone who has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Seek urgent medical advice for:
Increasing redness, warmth, swelling, or pus at the incision
Fever at or above the threshold given by your facility
Repeated vomiting or inability to keep fluids down
A rapidly enlarging abdomen or worsening abdominal pain
A wound that opens
A drain that falls out, stops working, or changes unexpectedly
And for anyone, someone who:
has abdominal pain that is severe, constant, or getting worse
has a wound that is hot, spreading red, or leaking pus
The article also says
Contact the surgical team about pain that is not improving, constipation, minor wound drainage, medication questions, or uncertainty about activity.
Every sign above is quoted from the sofidex article on Abdominal wall surgery. If you are not sure, err upward — it is always reasonable to be checked.