Genital herpes is an STI that causes painful sores on or around the testicle. This case study involves a nurse or doctor can help diagnose testicular tumors. Some blood tests can help diagnose the tumor or other underlying condition. Visit a sexual health clinic, GP, nurse, young people's clinic or a lump in the. Be sure to make and go to all appointments, and call your doctor or nurse may suggest that you do a regular skin self-exam to.