Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Use the emergency contact number supplied by the reconstructive team.
Seek emergency care for trouble breathing, chest pain, fainting, confusion, uncontrolled bleeding, or coughing up blood.
Sudden one-sided leg swelling with breathing difficulty also needs emergency assessment.
Contact your surgical team promptly for increasing redness, warmth, swelling, drainage, bad odour, worsening pain, wound opening, or a fever that meets the threshold in your discharge instructions.
Also call if a drain stops working, falls out, or suddenly fills with blood.
If you have a flap, seek urgent advice for a sudden change in its colour, temperature, swelling, firmness, or pain.
And for anyone, someone who:
Questions about scars, mild ongoing swelling, activity, or return to work can usually wait for routine office hours or a planned follow-up appointment.
Every sign above is quoted from the sofidex article on Reconstructive surgery. If you are not sure, err upward — it is always reasonable to be checked.