Cheating??

Today, I took the ACT. After the tests were collected, the test administrator/teacher called me up to see him after everyone else just left. He said that after reviewing my answer booklet, my test “might be void” because it looked like I’d filled in the answers to one of the previous tests that was already finished, but I didn’t. I know that it’s my word against his, but I didn’t change my answers. Will the ACT still void my test and cancel my scores? Can I do anything?? Please help me!!