Dude, the body will heal itself. Heating pads are a life saver. I've had it happen to me twice (one was my fault and the other was shitty ass gear), and the last one I thought I was going to have to go to the doctors to have it drained but my body ended up healing completely in almost exactly a weeks time. It's a big bitch, but time will heal.
Bad fucking advice, dude. The body will TRY to heal. If it's beyond your body's capabilities, we have to intervene with modern medicine. You can't just pray for mercy to the great Juice Gods.
If things aren't healed up and it's coming up to the 1 week mark, keep a close eye on it. It could just be the BA or high amounts of other crap some UGLs blast their gear with for sterility... but you can be like me and just sensitive to BA or other types of oils. Even pharm grade (legit - don't question me or my sanitary practices), I've had a few warm, tight knots in my muscle that took a few extra days to subside.
The worst is when I pinned some Karachi sust. Was as smooth as it always was bit for some reason my shoulder had tons of pain. Perhaps something got into the vial but it happened twice. This time it was so bad I had to put a pillow under my arm and get my gf to spoon me and wrap our legs in a blanket. Had to make sure I couldn't move because the pain was so excruciating. I'm also sensitive to UGL gear with lots of BA. It's the luck of the draw. Just do your best to employ sanitary injection practices, rotate injection sites and give them a little massage a few minutes after injecting and get the oil moving around. Like others have said, if you pin right before working out it'll get the blood moving and the muscles warmed up. It really makes recovery simple. Prop shots sometimes bothered me the next day but if I pin and train, recover is noticeably quicker.