The rear brakes are a Drum-in-Disc setup. Your regular brakes are disc, then inside the rotor (hub) is a small set of shoes and a drum-type setup for the parking brake.
Doubt you warped anything, you probably got it warm, just dont do it again, and change the brake shoes inside the drum if you are that worried about it.
The ebrake and regular brake are two different systems. The ebrake is the only thing that will be effected, your regular brakes are fine.