Suggest Remedy For Fever, Chills With Rash On Vein Long After Surgery

I had surgery triple bypass surgery in 95' and about once a year I start out with very high fever, chills, bad headache, and very weak, heart races, and about 12 hours later a rash starts breaking out on my leg where the vein was taken out for the bypass. It get bright red and spreads along my leg and foot. I break out into a terrible sweat and then the fever breaks but the rash gets worse for a few days and starts going away. I've seen specialists and my heart doctor doesn't know what causes it. I'd like to find out what this is. I am 72yrs and it's affecting me more each time. Buddy