If you accidentally swallow it, like if it works it was in your sleep or something... it's gonna be a worse proceedure:
Chronic Ingestion of a Zinc-Based Penny -- Bothwell et al. 111 (3): 689 -- Pediatrics
Chronic Ingestion of a Zinc-Based Penny
Dawn N. Bothwell, MD and Eric A. Mair, MD, FAAP
Department of Otolaryngology-Head and Neck Surgery
Walter Reed Army Medical Center
Washington, DC 20307