Im just stopped iv drug usage a week ago and in the spot where i shot up last theres a hard red bump thats painful and getting bigger and harder?

See doctor: First of all, congratulations to you on stopping IV drug usage. Please be sure to get into a program and a support group to help you stay off them. A hard red bump is a sign of infection (abscess) and needs evaluation. It may need to be drained. If infection spreads out of the bump and into the surrounding skin, that could get nasty.

Good job quitting!: Sounds like you have a boil or subcutaneous abscess developing. You need to go to ER so they can examine & possibly drain & culture it. You absolutely need antibiotics right now. I would push for further testing (HCV, HBV, HIV & blood culture) & maybe even echocardiogram to look at heart valve leaflets to make sure those don't have vegetations on them. Endocarditis is common in IV drug abusers.