Hello, I Have Had A Persistent Large Rash Across My

Hello, I have had a persistent large rash across my right breast then a few random spots of the same type of rash(smaller than a dime size) under my collar bone and a small spot on my left breast and on my right forearm, my breast tissue seems to have less elasticity that previously and when my breast is manipulated you can see clear lump type bumps but those may be veins?