No, the sin goes away...
Of course there are rules, but you are going to want to follow them... and you're forgiven if you fail.
I knew there was a catch!That sounds good...
Accepting the sacrifice of Jesus isn't about being able to break the rules with impunity. In any relationship there are rules. In a healthy relationship, you don't follow them because you have to, you follow them because you want to.
The key here is that after accepting Jesus' sacrifice, a fundamental change comes over your heart. You won't feel like you are restricted from doing the things you shouldn't, you will be happy that you don't have to be a slave to those things anymore. Will you still screw up? Of course! Are you forgiven if you do so? Yes.