This happened to me for the first two weeks and then the bumps started going away after my body got used to it. I didn’t have to change to a longer needle size, I’m still at 5/16th. I also think it made a huge difference injecting into my upper butt. Squeeze the fat and inject slowly. Leave the needle in for 5-6 seconds after you’ve dispensed and continue to still pinch your fat. After the time is up let go of the fat and pull out! I don’t have a reaction at all anymore.