To be sure, you'll want to check with your County Board of Elections which can be found on your County's website. Call or email the Board of Elections.
That being said, more than likely... if you have not mailed back the Absentee Ballot you should be able to vote in person without issue.
The following is what I was told from a NY county Commissioner of Elections (who was a Republican, so take that with a grain of salt and double check to make sure you're not voting illegally twice in your state):
He said: "You can continue to vote in-person. If an absentee ballot were to be received by the county board of elections when someone had voted in-person and signed the voter log book, the system would catch it and the absentee ballot would be set aside as “do not count”.
NOTE: DON'T VOTE TWICE, IT'S ILLEGAL
North Carolina State Board of Elections:
"It is illegal to vote twice in an election ... There are numerous checks in place in North Carolina that prevent people from double voting."