If you mean the vote count on the question/answer:
Questions have a timeline, where you can follow this information.
allows you to follow the timeline of your question.
posts and the end by
Go try it for a more busy question, it takes a bit of practice to be able to read it properly...
If you mean the user's reputation:
You can see this under the
reputation tab on the profile of a user.
However, it doesn't show totals; so you'd have to count how his reputation has changed over time.
Although, the network profile
reputation tab shows a nice graph where you can get a better idea if the question has been asked long ago and it becomes unfeasible to use the user's profile.