This expression gets its roots in the movie "The Aviator" which was a biography of the famous entrepreneur responsible for the movie Hell's Angels and a lot of other things.
There was a scene in the movie where he locked himself in a room and didn't talk to anyone for weeks. He grew a beard and began peeing in bottles and had all of his food and drinks brought to him.
It is very necessary to go without shaving for a time and let your body heal. It's also important to avoid pollutants and keep away from things or people that can harm you.
Thus, pulling a Howard Hughes is a very endearing term, which means to cleanse one's self, to stay away from others and to draw within and heal from the inside out. Take good care of yourself and pull a Howard Hughes soon.
I'm gonna pull a Howard Hughes.