Check your followers list manually and compare it with a previous list or screenshot
Use Instagram’s own activity and notifications to spot changes in engagement
Search for the person’s profile to see whether they still follow you
Use a trusted third-party follower-tracking app only if you understand the privacy and security risks
Review recent unfollow patterns by tracking your follower count over time
Ask the person directly if appropriate
Export or record your follower list regularly so you can compare it later