If it feels like just a big knot, kind of like someone hit you, that's normally what I feel with any oil based AS. You should feel some discomfort, but usually that should go away after a couple of days as you mentioned. When you need to worry is when it doesn't go away after 2-5 days or so. Depends what, where, and how much you shoot. I've heard that if it starts to get hot, that could be the sign of an infection, but I don't have personal experience with that, thank God.