Baby's Armpits

My daughters armpits are red & raw. I've given her a bath & let her sit in it for a little to try to see if that helps. Also tried cortisone cream & baby powder to help keep them dry. I'm not sure would it could be? I can tell it hurts her when I touch it. We don't have an appointment till Wednesday. 🙁 Anyone else have babies with a similar problem?