Hi guys i need help on how to take the head off the engine.

I unscrewed 4 screws of the engine head in an X pattern but the last two screws got messed up really bad.. Now they have round heads and won't give me any grip to unscrew them, is there any trick to get the head off the engine?
like some pliers or something and damn i can't find anything slim enough to go though the space between the head fins, oh please tell me what to do i want to get it fixed as soon as possible.
Any help appreciated