Learning About Breast Cancer
Your pinking sounds fast - all the women I know got it about a week into RT. There must be some who have ultra sensitive skin who experience it faster, however you need to listen to your body and action your concerns. You would not have posted this unless it raised issues for you.
I would raise this immediately with the Radiation Oncologist in charge - ask to speak to them in person at the clinic + ask the RT operator how often their machines are recallibrated, when was the last date the machine being used on you was recallibrated and can they please double that check your dosimitry calculations are correct.
I only raise the latter three issues as unfortunately there have been some terrible cases of poorly callibrated RT machines and/or incorrect dose calculations burning patients badly. Google New York Times and radiation for the series that revealed these problems. A signpost for these more serious problems was immediate pinking. Unfortunately some patients did not insist on getting immediate answers, and ended up with serious health consequences. I encourage you to raise your concerns now and not be a passive patient if you have something troubling you like this. RT is a serious, serious procedure and unfortunately the system for monitoring machines and errors is far from ideal - which means we need to be vigilant about protecting ourselves. Good luck and it would be great if you post what they tell you, how satisfied or not you are with their explanation and then how it all goes.