"Importantly, our results show that evidence of injection was more prevalent among decedents with xylazine and heroin and/or fentanyl detections. Despite limited literature on the health effects of chronic xylazine use, regular injection of xylazine has been associated with skin ulcers, abscesses and lesions in Puerto Rico.2 3 Semistructured interviews with people who use xylazine in Puerto Rico revealed that regular use of xylazine leads to skin ulcers.4 As skin ulcers are painful, people may continually inject at the site of the ulcer to alleviate the pain as xylazine is a potent α2-adrenergic agonist that mediates via central α2-receptors, which decreases perception of painful stimuli.1 People may self-treat the wound by draining or lancing it, which can exacerbate negative outcomes.8 While Philadelphia has seen a rise in skin and soft tissue infections relating to injection drug use, it is not yet clear whether or not this is due to increased presence of xylazine in the drug supply.9"

Source

Johnson J, Pizzicato L, Johnson C, et al. Increasing presence of xylazine in heroin and/or fentanyl deaths, Philadelphia, Pennsylvania, 2010–2019. Injury Prevention 2021;27:395-398.