Son caught his penis

So my 4yr old caught his penis in a drawer by accident. It immediately turned purple and swollen. I’m guessing he only caught the tip because that’s the part that’s bruised and slightly swollen, not the whole thing. Called advice nurse she says the worry is if it gets too swollen he won’t be able to pee. So he cried only a few minutes and was fine, peed normal no blood and swelling has stayed the same if not gone down. Would you take him in to the ER?? My hubby just got home and checked he says it’s fine, and taking him in they won’t do anything to help only cause unnecessary pain. What would you do?