There are two ways to check:
Daily notification — if enabled, you'll receive a notification when you enter OnlyFans showing that Auto-Follower has run. You can change Auto-Follower settings in the Console's Automation page under Expired Fans.
There are two ways you can know if Auto-Follow has worked on any given day.Your following page — check whether the number has increased at onlyfans.com/my/subscriptions/active.
Due to OnlyFans delays, the list may take a couple of hours to update.
For detailed results — including re-engaged fans and earnings — see the automation reports in the Console (see "Bump Online Fans Automation Settings and Reports" for the reporting layout).