I never specified her forehead. And those things you mentioned also constitute a person's appearance. I don't care what her makeup or hair is like. I would never make fun of someone for those things.
So you wouldn’t laugh at someone wearing clown makeup but otherwise acting serious?
I would assume they worked as a clown or something similar and were on their break. Also, clowns aren't funny.
I say fair game to anyone that intentionally alters their appearance in a stupid way.
What you consider to be stupid is subjective. But you're free to laugh at people all you want. Just like how other people can think you're not a very good person for doing so.