Your short trip to the doctor has really turned your world upside down.It all happens so quickly doesn't it and I'm so sorry you have to face more surgery. Seromas are annoying but not a matter of urgency.I had a mastectomy last year and got a seroma under my scar which had to be drained twice a week for 5 weeks.It's not uncommon.As for your flight to Alaska,that's a tricky one.If you finish radiation by end of February and you don't have burns/broken skin then you should be ok 2 weeks later.This is something to discuss with your radio oncologist before xmas I should think.I've had breast cancer twice(same breast)with full lymph node clearance and I don't have lymphodema,most women don't get it.I get abit of "heaviness"and I have to be careful with my arm but it doesn't stop me from flying or any other activity.Try not to worry about that because the odds are in your favour -especially if you only had sentinal nodes taken. Hope it all works out for you and you get to have that wonderful trip.
Tonya xx