A recurring fever after childbirth is a critical concern that requires urgent medical attention rather than self-medication. The fever returning once your medicine wears off suggests the current treatment may not be effectively targeting the underlying cause, which could be a uterine infection, urinary tract infection, breast infection, or surgical wound complication. Please contact your obstetrician/gynecologist immediately for an in-person evaluation, blood tests, or pelvic imaging. Additionally, Nimu P contains nimesulide, which is generally not recommended if you are breastfeeding. Your doctor needs to identify the exact source of infection to prescribe a safer, more effective alternative.