Thanks for the hopeful thoughts everyone!
David, unfortunately when I returned it is really deadish looking, so no cutting. But will see how it goes these coming days, we had an usually cool two days, maybe it can be tricked to think it is going into Spring.
Donald, you are so right, it is quite water needy here during summer, and it usually gets daily watering but due to the family emergency it was just on its own. Actually I lost several plants, but still hoping they may come back. Other casualties were my Gaillardia, Calamondin tree, Tropical milkweed, Brunnera macrophylla and lastly this bougainvillea. I thought my lantana was gone too, but it has bounced back, so I am keeping my hopes up, maybe bougainvillea will follow similarly although just being too slow.
JB, thanks, will see if cutting back will help. I was a bit hesitant to cut back, trying to see if it will grow new leaves, seeing my lantana grew new leaves on seemingly withered branches. A real hope builder!