Like I said....a contusion would explain it well enough to cover your ass.
...Did he draw blood? Did he test the interior of the wound for any infection present? Did he measure the actual pressure inside the compartment (this would be a definitive answer)?
Did he give you any antibiotics (doxycycline is usually a god one to start with)?
From what I hear you saying is that you thought it would be fine...but now it seems to be getting worse...spreading up your wrist, into your arm...it's textbook, man.
If you just told the doc that you think it's infected in the interior, he'd be on it.
It's a closed "compartment"...where do you you think it's going to go?
I'm not trying to be a dick- I wouldn't be here if I was...
And, I'm sorry, but this is a perfect example of harm reduction, and I also would like to see it stay. You really could help a lot of people, who might end up in the same situation, by sharing your story.
Go back to the doc, and just tell him you think it's infected.
You are a brave soul by starting this thread...it takes a lot to man up and ask for help...