Hello Shelby,
It is true that as comets get closer to the Sun more of their ice sublimates and the embedded dust gets blown off to form a tail. The further away the weaker the sunlight and the smaller the tail. Comet Holmes is unusual in that is occasionally "flares up" to become several times brighter (I think last OCtober the comet got 1 million times brighter. Not sure exactly what is going on but most likely it is due either to the exposure of a new and large chunk of ice which sublimates quickly or perhaps even the break up of the cometary nucleus. Given that Comet Holmes has done this before I would think that the former explanation is more likely.
Cheers - David