What Could Be The Cause Of Red Lumps And Excessive Sweating On My Body?

Hello Doctor, I am mother of 4 month old baby and last from 10 to 15 days I have red lumps like patches on my whole body. At starting It grows nearby breasts and from 3 days it spread in whole body . And last from 15 days I am having excessive sweating too . Please guide what s the reason of it and what medication should I take ? Thanks