Let me guess.. You are feverishly searching around every message board and getting a wide range of results. Everything from "dude, you definitely have an infection you need to get to hospital ASAP so they can drain that thing and you don't get septic shock" to "relax man, you are probably alright this is very common and expected".
Every situation is different but Ill go ahead and tell you mine and hopefully this will make you feel a little better. After my first inject I was feeling alright for about hours, just slightly sore then for the next 2 days the pain increased (right glute). At this point I wasn't so nervous and what I had read it sounded normal but maybe I needed to keep an eye on it. I went ahead and did the second shot in my left glute as scheduled. Both injection sites were now swollen and sore. Fast forward to day 8 which should be my 3rd shot and I still have lumps in both cheeks and an equal amount of pain in each one. The lumps were slightly warm to the touch but not red. At this point what I am reading on message boards about how long pain should last and lumps is making me very nervous. I started feeling feverish and took my temp it was at 98.8 (I am usually around 98.0). I went into a slight panic and was Googling everything I could about septic shock, abscesses and how to aspirate them. In the span of a half hour my fever spiked up to 99.1 then up to 99.5. I decided to aspirate the site after getting the details of how to do it yourself (which isn't a great idea by the way). Drew blood but no puss. I called a buddy of mine who had done a few cycles and he told me to calm the F down and I was probably giving myself a panic attack. After another look on Google I found that anxiety can give you a fever. I layed down, played some calm music and my fever went away. Went and drank a glass of wine to calm myself and closed my computer so I could read anything more from the "experts" on the message boards. The next day the pain was starting to subside in the first injection site. I would say that it took well over a week and a half, maybe almost 2 weeks for that first site to go back to normal. I started rotating in quad injections and soon the pain would go away quicker from shot to shot and I stopped getting the swelling after a few. There were a few weeks there where I would feel pain in all 4 injection sites at the same time (quads and glutes) and sometimes it was impossible to walk normally or sit down without something hurting. I think my body just didn't like what was happening. Every body is different and everybody's gear is different so you will get a wide range of differences on sides. I was seconds from going to the emergency room and if I had not talked to my buddy and calmed down I would have. I never found anywhere that said having pain for a week and a half is normal or OK. It seems like if there is a major problem you will know its a major problem without having to ask.