So, i downloaded a Torrent with a few video files, but seems like one of them got damaged(You are seeing it, and then at one moment the image distorts, and returns). I'm not sure if this is because the original file was like this, or if there was a problem with the download, so, Is there a way to erase only that video file, and have the Torrent client download it again? I'm using BitTorrent, but i can change to another if necessary.
Yes, you can.
Delete that one video from the downloaded folder that you want to download again.
Then you have to import your torrent file to BitTorrent, and the download should start. BitTorrent might begin with verifying the downloaded files, but once it detects that a file is missing (the one you deleted), it will start downloading.