I changed the pads and rotors on my 05 Outback at the end of May with Hawk HPS pads and Centric rotors. There have been some squeaks, but overall they've been great. I've noticed a squeak/squeal after driving on the highway, but not enough to warrant a real inspection.
I happened to take a peak at the right rear wheel this morning, and saw this bubbling near the pad. I'm presuming this means that the caliper is seized, or was at some point, and the grease boiled?

What's the best course of action here?
I happened to take a peak at the right rear wheel this morning, and saw this bubbling near the pad. I'm presuming this means that the caliper is seized, or was at some point, and the grease boiled?

What's the best course of action here?