I had it taken care of in late october last year, but it seems that its already come back. The dog leg on the rear quater of the wagon has what seems to be bubbling underneath the new paint.

excuse the bad picture quality. Its clearly rust, and its on both sides of the car. The passenger side is worse than the drivers side.
The surface hasnt broken yet but im pretty sure it will soon. Its in a bitch of a place, and im wondering what kinda prices would be involved in getting 2 new rear quater panels and replacing these- Or would cutting the affected area out with a grinder and replacing it be easier?
Id take it back to the panel shop that did it originally but my mate works there and aparently ive been 'running my mouth' about his shoddy workmanship on my car.
Anyone else had rust in tight places like this? What'd you to go get rid of it?