What to inspect
Check the drainage hole and cachepot, then inspect roots only when persistent wetness or rapid decline justifies disturbing the plant.
Choose one evidence-based action
Remove clearly dead tissue with clean tools, use fresh draining mix, and stabilize light and temperature. Do not repeatedly water a damaged root system.
What not to do
Do not diagnose root rot from one mark, change several major conditions at once, or use an unlabeled treatment. Old damage may remain after the cause is corrected.
Review the outcome
Photograph the same area under similar light, record the date and intervention, then compare the boundary of damage and the quality of new growth. Escalate rapid decline or safety concerns to an appropriate professional.