I’m pretty sure that you are stuck with it. I don’t know how bad the typos are, but they probably aren’t a deal breaker. The person reading your letter of intent is likely reading through a whole stack of letters. They might not even notice the error.
During APPE rotations, I had the chance to hear some programs discuss people from their application pool. I heard a story of one person who’s application got tossed after an interview. The current resident was saying how tired he was and the applicant said not to worry and indicated that she gets tired sometimes too. It was taken as a bad sign. Everyone, programs included, gets a little obsessive about the match. To some extent, it’s impossible to predict and control how you will be perceived. She was trying to be kind, and a different resident/program might have seen it as a nice gesture.
I didn’t match last year. If I could change one thing about my approach to applications, it would be eliminating the pure anxiety I felt at that time. It would have been healthier, and I would have done better during interviews. Don’t let a tiny mistake eat at you.