I don't have much to work with but I remember watching a movie, a few years ago that was a cartoon if I remember correctly. And in this cartoon some kind of virus or something was spreading and some animal had it, the virus, or whatever it was, looked like the skin of the animal was covered in pink worms. I also think that somehow the main charcter got this virus only on one of his arms. If anybody knows what this movie is please help its been bugging me for a long time.

Osmosis Jones?

Older than that. Good try though. Thanks.