Hello, I feel flushed(low grade fever) and have about 6 red welts on the back of my neck, which sometimes tingle. Started yesterday, had a flu shot this AM Have taken 1 benedryl..doesn t seem to have any effect. Have slight chills also Since I am going out of country Tues, my walk in MD gave me Keflex, 500 mg, which I have not yet taken. Any suggestions?