I recently had an experience with a bicep injection/infection that landed me in the hospital. The problem is that if it is an infectionand it goes systemic, you can get very sick in a hurry(that's like dead sick). These docs were not fooling around and slammed me in bed with massive iv antibiotics when I was feeling fine. So I guess my advice is, if it is swollen and red, warm to the touch, it could very well be an infection and needs to be taken seriously, ie go to the doc. This is the reason that I no longer do biceps and chest, just too risky imo.