Despite the fact that I proofread my cover letter a dozen times, and had a member of my career center proofread it twice, there is a very small typo in my cover letter. The word "in" is missing from a sentence "to be used [my school's] classes." Obviously there should be an 'in' there. I've already gotten one interview from a judge who received a cover letter with a typo, but I am concerned this could hurt my chances with others.
Thoughts?
Nothing snarky please. Yeah, I know I should've seen the typo. It was a stupid mistake.

But I obviously cannot do anything about it now.