When you say you "executed" the sprint, this means that you completed the code for the feature(s) you committed to and that the feature(s) passed the acceptance tests your Product Owner helped write. Absent passing these tests, the feature isn't done--at least not according to Scrum (which I presume you are using if you mention a sprint and Product Owner).
If a feature doesn't pass, it isn't done. If it passes, then it is. Now at the demo at the end of the sprint, maybe other stakeholders feel the feature should do something else in addition or whatever. In that case, the new feature is added to the Product Backlog as a user story and sized and prioritized like any other.
What you describe might occur during a sprint where you just show the Product Owner something to satisfy his or her curiosity, but the only feedback that matters is passing acceptance tests that indicate the feature is production-ready.