It the fluid level in your radiator going down? Any oil present in your antifreeze or vice versa?

In my experience a bad head gasket does not cause overheating, the lack of antifreeze because its leaking/burning off causes it. I have heard of head gaskets going bad from overheating though.

While it may be a problem, in my mildly experienced opinion, its not THE problem. Unless you are burning through antifreeze that quickly.

If revving the engine helps it sounds like more of a flow problem. Either air or coolant. I would.start by running the engine with a large fan blowing right at it. If it still overheats its likely a coolant flow issue. If that solves it, its likely a bad fan or a dirty radiator/condensor