Under breast redness, irritation and bumps

So, today was first day where it finally got warmer, so I just wore a T-shirt and underneath it my usual bra. I admit I usually go around without a bra because I’m a little heavier and have close to a cup size D, though I always was a cup size C. Long story short, today I really noticed a red rash underneath my breasts which looked quite inflamed and was exactly the area which was covered by my Boobs. I also noticed little bumps and raised skin that almost looked like skin tags. I’ve noticed this also sometime last week after sweating, but it didn’t bother me much at time, but today it is because once I washed myself up (soap and water), it stung so badly!

Amidst Covid 19 I don’t want to go to pharmacy or doctor, so does anyone have a good recommendation on how I can treat this? I realize keeping that area under my breasts will need to be a priority, in just wondering if anyone has good suggestions on how to do that? I used some apple cider vinegar to try to disinfect the area and also dabbed small amount of baking soda on the affected area.... any other ideas?