How do you make a scab on your face less noticeable without making it noticeable seeing the makeup on the scar?

I'm no expert but I would test around with some different concealers. Just remember that less is best when trying to cover up something so don't cake your make up on... If you enhance you eyes or lips with make up it will also draw attention away from the scar.

Try using a cover stick, which is a stick version of a concealer. These will give you a full coverage and make the scab less noticeable.