There is no cure for dengue. Patients in wealthier countries generally fare better than patients in developing regions with limited access to medical interventions like blood transfusions and places where waves of dengue patients overwhelm already-strained healthcare systems. Two dengue vaccines are available in some countries, but both have serious limitations in terms of efficacy and how long they confer immunity.
Here's the linked article about the state of the vaccine: https://doi.org/10.1016/j.jvacx.2024.100604