You should start a new campaign to attract new followers.
The Campaigns dashboard will show you a variety of metrics related to your followers campaign, such as the number of times users see the ad, the number of times it’s clicked on, your follow rate and your cost-per-follow (CPF).
The Followers dashboard allows you to track your follower growth over time. You can also use it to discover valuable information about your new and existing followers, such as their location, gender and interests.
You can get a comprehensive view of the metrics for all of your Tweets, both paid and unpaid, in the Tweet activity dashboard.
There is no opportunity to add followers from earlier timeline.