The only accepted way to erase data from a hard drive using magnetism is through a process called degaussing, which involves using an extremely powerful electromagnet which alternates its polarity thousands of times a second. It is the changing magnetic field which erases data, not the presence of magnetism itself. A human being cannot rotate a magnet fast enough to effectively degauss a hard drive. Most likely, if you put a strong magnet to a hard drive, you will just damage the delicate head inside it, but not irrecoverably destroy all the contents of the drive.
So yes, data most likely can be recovered from a hard drive that was exposed to a magnet held to it by a human.