What Could Cause Persistent Lower Abdominal And Right Testicle Pain After Oral Sex, Despite 4 Days Of Doxycycline?

Hi, I am 40 year s old man. I received oral sex from another man, and two days later I started having pain in my lower abdomen and in my right testicle. I went to my doctor who prescribed me doxycycline for 8 days 200mg daily. After 4 days I feel exactly the same way... what could this be?