Yes, totally random, but I feel like sharing this for the fun of it…
Nosebleed happens because some thin blood vessels in the nose just explodes due to some environmental changes such as weather (hot\cold), nose blowing or blood pressure raise (Or even nose picking) because these vessels are really close to the surface.
Treating it would be by pressing it, holding your head up high and teabagging your own face with ice bags. That, and stop watching hentai would help alot =P
I’m glad this doesn’t happen to me, but my bro used to face something similar whenever the room gets cold… I tell ya, it’s not funny when he wakes up and blood covers his face. Freeks the crap outta my pooper!!
I added a source link down below because it has some better explanation (And funnier pictures).