I have a bump about 1/2 inch (diameter)red, purple behind my right ear. Not painful. it started as a smaller bump a week ago. At the same time, i had flu like symptom, sore throat, bad cough and etc. Have seen a doctor, after taking Amoxicillin for 6 days, the flu symptom got a litter better but still feel weak. I am male, 52. No other known health issues. Is it a serious issue? Thanks.