Chickengunya is not prevelant in Washington DC however as you have red spots only on bums so it could be any thing . You must check your self with a physician near by you and have investigations done as soon as possible as head ache and nausea is not good symptoms. Don’t wait for on line answers or treatment
Next Steps
Consult a physician or internist near by hospital ER
Health Tips
Investigations if blood probably an possible MRI