Dog licks my nose.

Hi, Luci was diagnosed with Lymphoma and also had 3 Mast Cell tumors removed back in early April, and at that time was given 2 weeks to live. She was put on Presnidone, Tramadol, Benedryl, and Pepcid at that time. Ten weeks later she is still around, has gained some weight, I assume due to the Presnidone, had started to have mild seizures,was put on another drug to control them which it has. I realize she is end stage, but she seems to always be in good spirits, eats well, and other than a little incontinece a night while sleeping once in a while, is doing o.k. I don't think she is in a lot of pain. My question is more of a behavioral one than medical. Since she has recovered from surgery, she has an obsession with licking inside my nose when ever she can get to it.She sleeps next to me every night as she always has, and going to bed gets difficult because of this obsession. We have two other Italian Greyhounds, they have always slept by my wifes side. Luci has always been my little girl and favors me, always has, but has never done this until she got sick. Would there be anything that would cause this? My main concern would be if you would think this could be a reflex to pain. I would never want to keep her around for my benefit, but I don't think she is in any pain right now. Any ideas? Thanks..