Painful rash on chest (pics)

I tried to call a dermatologist today, but left a message. (47m) It started as light red bumps on my chest (below my right armpit, intersecting right of my right nipple) as of Saturday. As the time carried on, it got worse… and painful, not itching. I took pictures starting Monday. Today (Wed), it got worst. It’s localized, not spreading, no other rash on my body. My tricep area on my right arm has sensitivity. It’s also the same area that rubs against the rash, but no signs of the rash on my arm. Never had or experienced anything like this before. STD free (recently tested), not sexually active. No history of any skin allergies. Had chicken pox when I was 6yo. I only have HPB and cholesterol, managed with meds for the past several years. Since the last pic dated Wed night, should I wait until I contact dermatologist tomorrow or should I see urgent care? [ https://imgur.com/a/byI72vM ](https://imgur.com/a/byI72vM) Is there anything I could do in the meantime to either reduce the inflammation or the burning pain when my shirt touches/rubs against it?