Are you sure you didn't do that on purpose?
The old flirting with getting outed syndrome.
Now you have had to create a big lie to which you will have to continue to lie about.
You should have acted like it was nothing and called him about the project.
This is a case of if YOU don't make a big deal out of it it won't be a big deal to your friend.
You have peed in your oatmeal enjoy.