Fragile Remedy by Maria Ingrande Mora

Sixteen-year-old Nate is a GEM—Genetically Engineered Medi-tissue created by the scientists of Gathos City as a cure for the elite from the fatal lung rot ravaging the population. As a child, he was smuggled out of the laboratory where he was held captive and into the Withers—a quarantined, lawless region. Nate manages to survive by using his engineering skills to become a Tinker, fixing broken tech in exchange for food or a safe place to sleep. When he meets Reed, a kind and fiercely protective boy that makes his heart race, and his misfit gang of scavengers, Nate finds the family he’s always longed for—even if he can’t risk telling them what he is.

But Gathos created a genetic failsafe in their GEMs—a flaw that causes their health to rapidly deteriorate as they age unless they are regularly dosed with medication controlled by Gathos City. As Nate’s health declines, his hard-won freedom is put in jeopardy. Violence erupts across the Withers, his illegal supply of medicine is cut off, and a vicious attack on Reed threatens to expose his secret. With time running out, Nate is left with only two options: work for a shadowy terrorist organization that has the means to keep him alive, or stay — and die — with the boy he loves.