"I'm feeling a lot better, with a long road in front of me," Olsen wrote. "After my freedom of speech was quite literally taken from me, my speech is coming back but I've got a lot of work to do with rehab."
The post is accompanied by a photo of Olsen, smiling with a neck brace on and a visible scar on his forehead.
"Thank you for all of your support, it has meant the world to me," he continued. "You'll be hearing more from me in the near future and soon enough we'll see you in our streets!"