Wow - the book sounds very interestingly written! "I'll be blowed" is an English exclamation, similar to the more American "I'll be damned". Very hard to explain, especially in this context. Normally it means, "I am not going to stand for it if they do.....to me", e.g. I'll be blowed if they think that I'm going to pay them the money". However, in this sentence, the first bit literally means: "I am dirty and sweaty", but the way it is written has been used for exclamation purposes. Confusing, I am sure - any further questions? Tom

The expression is part of a non-standard English phrase used to express strong emotion, "blowed if it ain't..."