Sorry that you had to experience such a terrible ordeal. Sometimes we learn the hard way. Learning being the definitive word. It sounds to me that you not only put your trust in an inexperienced dominant (and i use the title loosely), but that you, yourself, realize it now just by the aftercare you received.

Look to the bright side, you have to kiss many a frog before you find your prince. I say kiss this frog good-bye and chalk it up as a lesson learned.