POISON IVY 9 days before wedding

On Friday, I started noticing raised spots/welts on my chest. They were incredibly itchy and I thought that somehow I got poison ivy. I started using witch hazel and hydrocortisone cream. Since, it's developed and spread. We are currently away on Nantucket and my doctor told me to send her pictures of my chest, and she send over a prescription: prednisone and a steroid cream. Well... I'm super nervous about taking prednisone because I've read that it can cause nerve issues in the eyes (I am already fully blind in my left eye due to nerve damage) and major anxiety. I don't really want to take it. I did apply the steroid cream and it was supposed to reduce itching but instead, increased it! It also caused huge red spots around my little welts and almost seemed to "thin" out my skin. I took it off immediately in fear of an allergy and now I am at square one with nine days left until our wedding and a strapless gown. I am going to call dr. back today. Help! What suggestions do you have?