The Exo-Skin was an invention of Dr. Nora Wakeman that was a replace for Jenny's poorly-made "human" skin.
She uses the skin to hit on Don Prima at Mezmer's. Unfortunately, when the exo-skin attaches to it's host there's no escaping from it's grasp. Thankfully, Jenny is able to free herself from it's control by pooring a milkshake on her. After a short fight, she supposedly kills the exo-skin. Although, after Jenny and the other teenagers leave, the exo-skin latches onto Mezmer. Neither the exo-skin nor Mezmer appear for the rest of the series.