My friend got hit in the crotch and now one of his testicles is very swollen?

My friend was playing with his little sister and she jumped on him and ended up landing on his crotch weirdly. He is in a lot of pain and I convinced him to let me take a look (I did some medicine schooling) and his left testicle is very big and bruised. It hurts him very much when it is touched.

I think he should see a doctor but he is downplaying it despite his obvious pain. Am I overreacting, will it go back to normal or does he need medical attention? He won't let anyone else look because of how much it hurt when I did so no one else really knows whether it's that bad or no.
My friend got hit in the crotch and now one of his testicles is very swollen?
Post Opinion