I Am A Daily Heroin User. And Today I Shot

I am a daily heroin user. And today I shot up and I think I missed. I've been using the same area in the inside of my elbow for a week or 2 now and ever since I missed a couple hours ago it is very painful and sore especially when I try bending my arm. It is very tender around the area I am just worried something will happen to my arm or is happening to it.. What should j be worried about