Can i die from peritonitis if i ignore it?

Yes: Hard to imagine that you would ignore this complication of bowel perforation with growth of bacteria (from the gut) in the open spaces in your belly. This will cause high fever, striking abdominal pain, nausea, diarrhea and severe sickness. This is a true medical emergency and needs an ambulance ride to the emergency immediately.

Yes one of: The lethal infections of body , need urgent intervention of the cause ( some times surgery ) antibiotics and fluid management to avert the lethal out come, so can't ignore it.