Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Seek emergency care for severe or constant pain, repeated vomiting, a rigid abdomen, fainting, confusion, fever with worsening symptoms, blood in vomit or stool, or inability to pass stool or gas with increasing swelling.
Contact the treating team promptly if vomiting returns, swelling increases, pain worsens, bowel movements stop unexpectedly, or a surgical wound becomes red, drains fluid, or opens.
And for anyone, someone who:
Follow-up depends on the cause and treatment.
After discharge, clinicians may review bowel function, hydration, nutrition, medicines, wounds, and recovery.
People with cancer, inflammatory bowel disease, hernias, or movement disorders may need specialist care.
The article also says
Follow instructions about diet, activity, lifting, wound care, and returning to work.
Ask before restarting laxatives, fiber supplements, or medicines that affect bowel movement.
Every sign above is quoted from the sofidex article on Bowel obstruction. If you are not sure, err upward — it is always reasonable to be checked.