There is no detail in the highlights, so nothing will be recoverable. In the future, for shots like this, what you should do is expose for the sky: say for example the sky requires a shutter speed of 1/200 at f/8, and the wall is a shutter speed of 1/20 at f/8, you'd expose the shot at 1/200, and use a flashgun to make the wall exposed correctly too.
For example, this image:
Exposed for the sky, and used my flashgun and reflector. I took the flash off-camera, put a reflector behind me and the flashgun pointing into the reflector, and got a perfectly exposed image.
Hope that helped!