In order to return some of the affected data, you can use the recovery campaign.
The way it works is that you can select the time frame and message you wrote to the people. Then the campaign will retrieve the prospects that fulfill the given requirement.
Keep in mind that if the prospects are already in the existing campaign they won't be retrieved inside of the recovery one.
How to create the campaign
1. Add campaign
2. Select recovery campaign
3. Pick the name for it
4. Select the date range, the time, and the message.
(the message should be the message that you have outreached them with already)
5. Click apply
All the people who got that message are now pulled back and you can easily start a new campaign for them with the next messages you would like to outreach them with.
Then you're all set and done.