The moustache is markered on with Gundam line markers or any fine-tipped oil based markers (I never paint, always markers).
I did a few runs but in case you get it wrong, quickly erase it off with a soft eraser. Comes off easily too.
I also placed two pink dots as the blusher (Gundam marker again) and quickly blotted it out with a cotton bud for a soft effect.
Good Luck Tahra!