Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Emergency symptoms are different from routine follow-up concerns.
Severe shortness of breath, chest pain, a seizure, confusion, coughing up blood, or little to no urine requires immediate emergency care.
And for anyone, someone who:
Contact the treating clinician promptly if swelling returns, urine output falls, visible blood reappears, weight rises quickly, or blood pressure is much higher than the target provided by the care team.
And for anyone, someone who:
Follow-up usually includes blood pressure checks and repeat blood and urine tests.
Creatinine and eGFR show whether kidney filtration is recovering.
Urine testing tracks blood and protein, while electrolyte tests help identify problems such as high potassium.
Routine follow-up remains important even when urine color, swelling, or energy improves.
Urine abnormalities and high blood pressure can continue without noticeable symptoms.
The follow-up schedule depends on the cause, the severity of the initial illness, and how quickly kidney function returns.
The article also says
Body weight and swelling may be monitored during recovery.
A clinician may also review medicines because doses or choices sometimes need adjustment when kidney function changes.
Nonsteroidal anti-inflammatory drugs, such as ibuprofen and naproxen, can worsen some forms of acute kidney injury and should not be used without medical guidance in this setting.
Every sign above is quoted from the sofidex article on Acute nephritic syndrome. If you are not sure, err upward — it is always reasonable to be checked.