OMG need help fast

I like 72blu's method. If you get to where you think it's a valve or a cam lobe, you could just remove your rocker arms on that cylinder and do a leakdown test. If air blows out your carb or exhaust you know which valve is the problem. If it blows out through the crankcase you have bad rings. I don't know how to check the cam lobe other than watching the rocker arm move as somebody turns the motor over. Good luck.