My IJ had a bump on his nose, he ended up having to have it surgically removed. It was a mass of infected necrotic tissue, it would flare up and subside but then really got big. It was probably due to a rub on the cage latch, not totally sure what caused it though.
There is a thread in the Morelia section, I don't know how to link it from my phone and tapatalk. There is a pic of it though.