I know you've received some great answers that all advise seeing the doctor, but I wanted to make sure to tell you if he gets an erection that lasts over 4 hours (whether or not it's more painful than it is currently) he should go to the ER. penises need blood and if this is a vein thing, it could really cause some harm. Don't let him put it off too long; in fact, you could make the appointment yourself and inform him when he's going.

Unfortunately, that's what I have to do with my b/f. He hates the doctor and refuses to go unless I force him. Good thing he's more afraid of me if he skips the appointment than he is of the doctor. ;)