Piercing insertion is a common practice among people of all ages for different reasons (e.g., esthetics, culture, religion). In the oral cavity, the jewel can be placed in the lips, cheeks, tongue, and frenulum. The presence of an oral piercing could cause local and systemic complications in the short term. In the long term, irreversible damage may occur to the hard and soft tissues of the oral cavity. Different authors in the past have produced publications focusing on this issue. This study analyzes 10 published articles sourced from online databases according to the PRISMA flowchart. These articles were chosen from the 501 suitable papers initially found. PubMed, Web of Science, and Scopus were used as the online databases for searching for papers that matched the topic, using the keywords “complication” and “oral piercing”. The purpose of this review is to describe and analyze all possible complications related to the presence of a piercing in the mouth. Local and systemic complications are related to the presence of plaque and localized pathogenic micro-organisms that can spread via the bloodstream, although they rarely occur in patients without predisposing conditions. Maintaining proper oral hygiene and frequent check-ups are essential to avoid the onset of complications.