How do you treat swollen testicles with no pain?

Scrotal swelling: You need to be checked by a doctor as there are many conditions that can cause the scrotum to swell, from a tumor in the testes to fluid in the scrotal sac. Most likely you need a scrotal ultrasound and a complete exam to fully check the situation.

See below: If your testicles are not painful then there is probably fluid in the scrotal sac and not the testicles. You should get an examination and most likely get an ultrasound. You may have a hydrocele which is a fluid colection in the scrotum.