Where have they just come from?

"As the lights come up, Fraulein Kost is entering from the hallway with Second German Sailor. He pinches her, and she screams."

From this stage direction you can clearly see that Kost has been out with one of the German sailors, who she gives favours to for money.

From this you can easily get an impression of the kind of relationship they have, what they have being doing and what they are intending to do once they are in Kost's room. They clearly have a flirty relationship, and I get the impression that she has come in quite giggly and happy.

"Fraulein Schneider quickly emerges from her bedroom. She is all dressed up. She is also furious."

This quickly changes when Schneider comes out of her room and orders the sailor out of her house. They quickly get into an argument, which leads to Kost saying she is going to move out if Schneider doesn't let her bring Sailors back, as she won't be able to pay the rent.

In terms of hair and makeup, I think that her cheeks would definitely be quite flushed - she has just come from outside into a warm environment which would cause them to flush slightly, she's flirting with a man, and then getting into an argument causing her to get angry. These are all factors which would cause her cheeks to become redder. I think her hair wouldn't be perfect, especially after being outside - with the sailor.