Rising oil temp is no indication of a head gasket problem.
As already mentioned, has it recently been serviced and the wrong oil put in...
Hotter oil can be a sign of Big end bearings failing and they generate more heat as there is more play in them, or ot could be something as simple as a faulty sensor....
Id seriously check for big end wear though (Or any other wet bearing journals) - it was the first sign when I had my Skyline, that the bottom end was about to let go - thankfully I stopped before punching a hole in the block, though it turned out the engine was already past the point of no return