Abstract—Complications of parenteral narcotic abuse such as localized sclerosis of skin and subcutaneous tissue, indurations and nonseptic ulcerations were well documented, but fibromyositis is very rare. We are reporting an interesting case of pentazocine induced fibromyositis which presented as scapulohumeral and facial muscle weakness mimicking as FSHD. Interesting aspect of this case, which has not been frequently observed, is the involvement of muscle groups which were not injected with pentazocine. This case highlights the care that needs to be taken when prescribing opioid analgesics, such as pentazocine, as routine painkillers.