Re-entrance occurs when a patient repeats upstream processes during a single visit to the doctor. This study investigates the appointment scheduling of outpatients who may require stochastic, multiple re-entrances, and this is motivated by the Mohs Micrographic (Outpatient) Surgery for skin cancers. We develop SMART, a stochastic slot model that encapsulates the multi-stage nature of the service process, stochastic re-entrances, and heterogeneous no-show rates. We also propose a sequential scheduling algorithm designed for dynamic appointment requests. This algorithm efficiently balances patient waiting times, clinic overtime, and patient throughput, while accounting for stochastic complications.