thanks for reaching out to us in our forums and sorry for the delay in getting back to you! You can only contract Hep C from someone that is infected with the virus. So if the nail file or the blood smear was from someone infected with the virus and you yourself had an open wound than there may be a likelihood of contracting Hep C. However, only your healthcare provider would be able to officially run tests and diagnose you as well as provide you with medical advice.
Someone asked a similar question in our Q&A so I thought I would link it here: https://hepatitisc.net/q-and-a/contracting-from-dried-blood/ You can feel free to ask your questions here too.
Thanks again for reaching out.
Best, Lauren (HepatitisC.net Team)