Check your followers list manually and compare it with a previous list or screenshot
Use Instagram’s Activity or Notifications to see recent follower changes if available
Search for the person’s profile to confirm whether they still follow you
Ask a mutual follower if the account still follows you
Use a third-party follower-tracking app only if you trust it and understand the privacy risks
Review your own recent follower count changes over time
Export or record your follower list periodically to compare later