What can i do to address a purple rash in my armpits?

See your doctor: Your rash needs to be seen by your doctoror a dematologist to make a diagnosis it may be a contact dermatitis due to deodrant you are using, but purple rash needs to be checked.

Rash: This can't be diagnosed with the information that is available. A history, physical examination & other studies may be needed to determine cause/causes. Once accurately assessed a treatment plan can be developed.