Question

Ich schminke mich lieber als er sich.

is this incorrect or correct?

Answer 1

not really.

Ich schminke mich lieber als ...
means
I would rather put make-up on myself than ...

the "als er sich" sounds very clumsy and awkward and I cannot tell what you are trying to say.

Can you state the English sentence that you are trying to translate?

Answer 2

there is none. im trying to determine if that sentence is grammatically correct or incorrect.

Answer 3

This IS grammatically correct, but it sounds weird (no offense :P).
It means "I would rather put on make-up than he would", more or less. There would be better-sounding ways to say this although it is correct.