Hi I Am 41 Years Old And A Week And

Hi I am 41 years old and a week and a half ago I got red bumps on my hands that I thought were big bites. Very ichy and eventually a few of them turned into bloodblisters. The worst ones became blisters. Very painful and burning. Other areas of my body had splotched of red and look like welts. Went to ER and bloodwork all fine so he gave me steroid medicine that I take for six days. It working great until I was done with meds. It is now two days after the last medication and all of my symtoms are back. Even worst!!! What is happening to me?