Recently installed these on my 6G Accord. For some reason, what looks like rust is beginning to form in the "slots" where the pad doesnt make contact. How can I get rid of this, and prevent it from getting worse?

 

Perform a brake pad bedding. The heat should clear out most of the rust.

Rotors rust. That's just part of having a mild steel part exposed to the open air. The pad surface area should be cleaned up of rust by the pad itself when the car is driven, so it isn't a concern.

Maybe paint the non-contact area black? (Note, if you choose to try this, no NOT paint any of the contact surface.)