Your mask is nice (though you probably just used the lasso to "cut") but Osama's dpi doesn't match the mushroom's. Also, make an adjustment layer, darken the level, fill in the whole mask, then use the airbrush on a low pressure on white to reveal shadows on Osma's face. You might want to add a flare on a separate level behind him to reflect the light coming from behind (or maybe use "Glow" for a radioactive look).
"To all the camels I've loved before.
And dare I call myself a whore.
I may be right or wrong,
But I'm singing this ole song.
To all the camels I've loved before."