The COVID-19 pandemic has underscored the vital role of vaccination in mitigating widespread morbidity and mortality. Nevertheless, the global vaccination campaign has also brought to light rare but notable immune-mediated adverse events. Vaccination is inherently immune stimulatory, designed to provoke a robust immune response, and in rare instances, this heightened immune activity may unmask or trigger autoimmunity in genetically predisposed individuals. Proposed mechanisms include molecular mimicry, epitope spreading, and bystander activation, all of which can disrupt immune tolerance and initiate autoreactive responses. This case report explores a potential link between COVID-19 vaccination and the onset of dermatomyositis, adding to the growing body of literature examining the rare but important phenomenon of vaccine-associated autoimmunity.