Dynamic dosing systems for phototherapy and associated devices, systems, and methods are disclosed herein. In some embodiments, a dynamic dosing phototherapy system can include a self-service phototherapy kiosk (“SPK”) configured to emit UV radiation, a user interface communicatively coupled to the SPK, and a dynamic dosing system communicatively coupled to the user interface and the SPK. The dynamic dosing system can determine initial, user-specific parameters specific to define a first individual phototherapy protocol, and then determine adjustments to the initial parameters and the first individual phototherapy protocol based on user inputs related to erythema response to a previous phototherapy treatment session. The SPK can deliver UV radiation to a user in accordance with the first individual phototherapy protocol and/or an adjusted, second phototherapy protocol that takes into account the user's erythema response.