Step 1: the Eyes
It's very easy to make the eyes! First you want to make a 2 by 2 square (anywhere you want)
Then count 2 blocks going up and to the side and make another 2 by 2 square
Step 2: the Mouth
You may either: Look at the pictures then do it, or look at the pictures then read the stuff for this step.
First, you want to make a 2 by 2 square, touching the corners of the eyes.
Then you will want to have a row of 5 blocks at the bottom of your mouth square, and make sure 1 block is sticking out on each side.
Now you want to have 1 block sticking downward, beneath your sticking out squares from the sides.
Now you want to dig deep down, as deep down as your creeper face is carved into, and surround it with Netherrack.
Step 3: Filling in and Finsihing
Now for this step, you wanna grab some lava, because you're gonna want to fill in the eyes and mouth.
And now you're done! You have your very own lava creeper face. You can do this with water too, or leave it empty.
I hope you enjoyed my first instructable!