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, chest pain, fainting, confusion, or other severe symptoms.
These are emergency concerns rather than issues to wait on until a routine follow-up visit.
Seek urgent medical assessment for severe or rapidly worsening abdominal pain, persistent vomiting, a hard or very tender bulge, skin over the hernia turning dark or red, or an inability to pass stool or gas.
For routine advice, contact your surgical team if you have increasing wound redness, drainage, fever, worsening pain, repeated vomiting, trouble passing urine, or swelling that continues to enlarge.
Also call if the wound opens or you develop a new bulge.
Every sign above is quoted from the sofidex article on Ventral hernia repair. If you are not sure, err upward — it is always reasonable to be checked.