The 17-year-old has cleidocranial dysplasia, which affects the growth of his bones and teeth

Gaten Matarazzo is ready for surgery number four.

The Stranger Things star, 17, shared a photo on Wednesday from the hospital before heading into surgery for his cleidocranial dysplasia, a rare genetic disorder that affects the growth of his bones and teeth.

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“Surgery number 4! This is a big one!” he wrote on Instagram.

After the surgery, Matarazzo is doing “well,” his rep tells PEOPLE. The actor also wanted to emphasize that these surgeries are expensive, costing upwards of $40,000 each, and often not covered by insurance — a problem for cleidocranial dysplasia, or CCD, sufferers. Matarazzo has already had several surgeries on his mouth, but he has a “very mild case” of CCD compared to others, he previously told PEOPLE.

“There’s a one in a million chance that you have of getting it — most likely you get it from a parent, but it just happened for me,” he said in 2016. “I have a very mild case so it doesn’t affect me as much, but it can be a very difficult condition to have.”

He does, however, think that it affected his career.

“It’s one of the reasons why I haven’t been getting roles, because of my lisp, and the teeth situation, and my height,” he said in 2018, during an appearance on The Doctors. “That affected pretty much everything. I would go three times a week for auditions all the time and get constant ‘no.’ ”

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That all changed in 2015, when he landed the role of Dustin on Stranger Things. Matarazzo says his disorder actually helped him get the part.

“It really started out when I was stretching in the audition room,” he said. “They were like ‘Wait, wait, wait what did you just do?’ and I said, ‘What? I’m stretching’ and they said ‘No, do it again and they said ‘Why do you do that? Your shoulders are touching.’ … So I started explaining what it was and how I had a condition from birth that affects my teeth and everything. That’s why I was missing teeth in the first season, and I still have my appliance in right now.”

Matarazzo now works with CCD Smiles, a non-profit organization that raises money and awareness for people with the condition. He told PEOPLE in 2016 that his role on Stranger Things helped bring more attention to CCD.