coolant on top of piston

[sevenmgte]

my car keeps on lossing coolant and i don't know where it gos there is no coolant leak on the car but when i drive around for 15, 20 min it would spet the coolant back out. i was reading on the forums and people say its the hg. but i just did a 2.0 mm HKS hg on my car about a year ago and i wasn't boosting any psi and still have the stock ct26. i check my oil it looked fine, but forgot what kind of color that was comeing out of the tial pipe. so i left my car untouch for two weeks. untill 4/28/08 i started working on it i thought it was my water pump so i was going to replace it. i took everything off and was going to put the new one back on, but decided that might as well check the head gasket sens im under the hood. so i took every thing off and when i went to pull off the head i found coolant and oil on top of the piston. is that bhg or jaket leak???? but its 2.0 hks hg can it do that? can any one out there till me what i did wrong on my first hg change or was it some thing else. is the block still good? can i reuse it? do i need to resurface the head?sorry asking so many question.