I just had a similar sitation as I am running prop and tren usually mixing them together. I shot 1cc of prop into my tricep and my arm was red from elbow to my delt also it was warm but I didn't get a fever. I masaaged the crap out of it which hurt like hell,took some motrin and 3 days later it went away. It was the first time I injected into my tricep and also the first I didn't cut the prop. If you get a fever then go see a doc.