Potterlady, it seems from what I've read on this board that you may have a 3-5 days of use before your face starts to show redness. If you begin now, you'll be at your worst on the 25th. If your dermatologist agrees to postponing treatment, maybe you'd want to begin on the 23rd, if you aren't planning on going anywhere on New Year's Eve.
I have the same treatment plan as you and was going to start last night but, will begin instead, this morning. Hopefully, as I write during treatment, there will be some who have already been through this that will be supportive, and others that will post how their treatments are going, as well. This board has been an awesome resource. It seems to me that it would be a good thing for any medical personel that prescribe this treatment to have gone through it first themselves, as we don't get much info from them. I'm trying to calm my anxiousness about what is to come but, I must do it and am looking forward to when it is over.