Bedlam Boyz

From the Back Cover of the Baen first edition: "Healer's crusade - Kayla was one tough cookie. A runaway herself, she looked after other runaways and made sure they didn't get into more trouble than they had to. The trouble came looking for her. When one of her friends gets gunned down by an armed robber, her latent healing powers come to the fore. Kayla healed her friend - and the gang member who shot him. Now the gangs know about her - and want her power for their own, and only for their own. But the emergence of this tremendous power wasn't noticed by just the mortal denizens of Los Angeles. Soon, its not only the gangs who are after her, but also an ancient unnameable abomination lurking in a warehouse, plus evil elves from another world - and one human woman who just might save her, if only Kayla can learn to stop running..."