The Skin Factory

Chase is trapped in a netherworld factory where he's forced to build human bodies for dark beings known as the Wardens to infiltrate our world. When Chase overhears a plan to infect humanity with soul eating spores called the obsidious, he escapes the Factory to save his mom and sister, Andi. Only there's a mix-up and Chase accidentally possesses a girl's body to escape in. 

In our world, his mom is confined to an asylum, while Andi has already been infected with the obsidious. If Chase can purge the stuff from Andi, convince her he's really her brother, maybe they can save their mom. But whatever is locked inside the asylum might be the very evil Chase came back to save them from. 

And it's been expecting him...