I am not sure why this rash appeared under your breast on the side you had surgery but it would definitely be worth mentioning it to your medical team so that they can advise you on how best to treat it. So don't hesitate to get in touch with them and flag this.
Feel free also to get in touch with our cancer nurses for advice and guidance - you can call them on this free number 0808 800 4040 - their helpline is open Monday to Friday from 9am to 5pm.
I hope that this rash gets better very soon for you and that you manage to talk to someone about it.
