Dentist drained fluid under wisdom tooth gums, now hurts but can't have surgery for another 3 wks-- bad?

Sorry for the lame question phrasing-- it's a complicated situation and wouldn't fit in one line!

Long story short, I have an impacted wisdom tooth, and it's been swelling for about a month-ish, which I only notice when I wake up in the morning. It goes down a few minutes after I wake up, but never has hurt, just felt like pressure. I went to the doc today and he checked it out and pressed on it, and some fluid drained out from under the gum where it hasn't erupted yet (gross, but I guess that's why it's been swollen all this time...) It isn't infected, so I don't really know WHAT the fluid was. I thought it was blood based on the taste, but I guess it wasn't.

Now, after he did that, it does hurt a bit. Also looks a little bit darker back there. I am scheduled for surgery but can't have it for another three weeks, since I'm going out of town for two weeks after the next one and the doc wants me to be around after it in case of complications (it's risky due to a nerve issue). Is it bad that I am waiting three weeks, and at what point should I consider cancelling the trip to have surgery earlier? I'm concerned now since this tooth has never hurt before, and don't want to risk infection on an already-risky procedure, but I WOULD lose about 300 bucks if I didn't go on this already-paid-for trip. I did mention this to the surgeon, who just responded with it being better to risk waiting that until afterwards versus being out of state and recovering from surgery, but I don't know what qualifies as a tooth "emergency" or anything like that. How do I know if it's infected, or preferrably, how can I avoid infection for the next 3 weeks?

Thanks in advance...