Had shingle jab a week ago have a very painful and swollen arm headache and sweating been putting savlon on arm to try and ease it for the rash ?

First time or recur: The wording of your question suggests that you are familiar with shingles, having a "jab"? The treatment of the initial episode is quite different than treating recurring post-herpetic neuralgia/pain. I don't think Savlon, an antibiotic cream, should help. Initial rash & blisters best treated at home with moist compresses, calamine lotion, & topical cream for inflammation. Next, Rx. meds from MD.