WD elements put in MAC by mistake! WD HD not working on PC or Mac

Hi there, I wonder if some kind person could help and advise please. I have accidently put a WD Elements into my MAC thinking it was my Passport. I realised my mistake once I was unable to read the contents. I put the elements back in the windows PC and am still unable to access the files…It seems I have damaged it some how by putting the WD Elements into my MAC…am I correct? I would like to undo the damage if I can please so that the Elements works, or please advise as to how I can retrieve the information pon the hard drive. Thank you so much in advance…If someone could guide me to a previous post that may offer the solution that would be great too. I have had a look and from the subject titles I do not seem to see the same issue that anyone else may have had Thanks again.