Is it normal for testicles to shrink after squeezing?

Last week I was giving my bf a blowjob and as usual squeezed his nuts a little bit. He was really engaged and he was about to cum in my mouth, so I started squeezing harder and harder with one hand, pulling them down pretty hard. He usually stops me and tell me when he's uncomfortable but this time he didn't, so in the heat of passion I gave him all I had and crushed his nuts almost full force.

He grabbed my hair and pushed his cock deeper into my mouth, cumming a few seconds later. That was a mouthful, much more than usual as I can tell. He then asked me to stop and cupped his balls, smiling but agonizing in pain. After a couple minutes I inspected his balls, and even if he said to be ok, he couldn't move for half an hour.

One week later everything feels alright but to me his testicles seems to have shrunk in size quite a bit, like grapefruits when I roll them between thumb and index. Maybe it's just because we had more sex than usual, but I'm afraid I've dealt real damage...

As far as you can tell, Is it normal to cum more squeezing testicles? And more importantly, is shrinking normal after an hard squeeze? (I've gripped both testes with one hand full force for a minute or so)