I'm so glad that your family is OK after the accident, and I'm so sorry to hear that you've got this awful rash.
How long are you on the steroids for? I've been on 2 back-t0-back 6-day prednisone packs, and had a cortisone shot. All that did was spread the few initial welts I had all over my body. I saw a dermatologist who said prescribing the prednisone packs is the common mistake the family MD makes, and has given me a steroid foam and a steroid lotion that seem to be really clearing it up. I think my case was worse than most, so I hope your steroid prescription brings you speedy relief. I really feel for you! I've had this for 6 weeks now, and am just NOW starting to see the end of this.