pretty sure it's rosacea, going to dermatologist next week anyways (i'm on roaccutane course for two months now, so i'm going to ask my dermatologist about this red nose thing anyway, only last week i found out what rosacea acctually is lol so i'm definetely going to ask her about it). i'm not qualified at all to diagnose such things but my guess would be that i have both - acne and rosacea, but not acne rosacea (i don't understand what i have just written but i hope somebody does lol). so i'm just looking for an opinions by the way, i have had red nose for about 3 years already, so it's not related to roaccutane at all.
I'm off of accutane for 2 and a half months and i have noticed huge progression in my rosacea (so i have both, acne and rosacea, but almost all of my acne is gone by now, so I guess accutane was 50/50 for me). However, enough of this boring post-accutane rosacea, really interesting thing is that nasal herpes was actually the thing causing my nose to turn red lol. I did some research about nose herpes and I just found that it's pretty rare 
symptoms for me were nose turning really red and with huge gatherings inside. Anyway, i'm actually doing really ok, my skin is improving, marks are fading away, very light acne as i decided to drop out dairy products out of my diet and eat lots of veggies, fruits. i hadn't had herpes for a year now and i'm pretty positive about it. Even the rosacea, which is getting pretty bad isn't that much of a concern for me, because there are lots of ways contolling it and i'm going for an ipl treatment as i hit 6 monts post tane mark anyway.