Being "born again" doesn't cover you for anything, it's simply an adjective term for those who were once followers of the Christian faith, "lost their way", and re-discovered it once again. To obtain forgiveness (and enter the kingdom of heaven yadda yadda yadda) you must repent your sins (a primary part of "developing a personal relationship with Jesus").
If someone who already is a Christian sins, they don't need to be "born again", they simply have to ask for forgiveness while forgiving those who have wronged you.
Peter came to Jesus and asked, "Lord, how many times shall I forgive my brother when he sins against me? Up to seven times?" Jesus answered, "I tell you, not seven times, but seventy-seven times (or seventy times seven)." (Matthew 18:21-22)
Forgive, and you will be forgiven. (Luke 6:37)