What happened to my bike (Lost my Rear Brake)?

Unfortunately, I'm not mechanically inclined. I know I lost my rear brake on the drive home. Thankfully, I didn't have a 70mph stop on the highway, because I saw what happened at 45 when I stopped in the middle of an intersection. Can anyone point me in the right direction of how to fix this (crossing my fingers it isn't severe)? I noticed the gap in the seam in the one photo.

Cam cover gasket is chewed up there you can see its leaking follow the oil you might have soaked the pads with oil.

warp9.9 said:

Cam cover gasket is chewed up there you can see its leaking follow the oil you might have soaked the pads with oil.

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Thank you. That helped me with where to go from here.