I am so sorry for you, and sorrier that I didn't see this thread until today (I've been away from the forum due to other real-life "stuff" this week).
When I had a reaction that strong, I went to the doctor. She prescribed prednisone. But if you can't/weren't able to get to a doctor, allow me to recommend, first,
Tecnu: you can wash both your clothes and yourself with it. The U.S. Forestry Service recommends Tecnu to its field staff, so at least there's that much going for it. The price is right, but unless you get right on the exposed area within a day or so, Tecnu doesn't seem to be as effective.
Thus my second recommendation:
Zanfel. This stuff costs beaucoup bucks (the last time I purchased a tube, it was $38), but it
works. It doesn't seem to matter how long after exposure one applies the Zanfel to the skin: the stuff will reduce the itching (if used as directed) quite rapidly. Only a very little, maybe a half-inch "pearl" of the stuff, works up in your wet hands to a lather which is then applied to the skin. Do not apply to the conjunctiva of the eyes, just to the skin of the face.
I hope you're feeling better by now, but lay in a supply of these products, both of which are available at a regular drugstore. They're marketed as anti-poison-ivy products, but I personally have used both of them when exposed to juniper sap (yes, regular old juniper) and even unknown substances in the garden, which made me look and feel like you look in your photo and, I'm sure, feel/felt as well.
Cynthia H.
Sunset Zone 17, USDA Zone 9