I Am A 48yr Old Women Who Ha S Used

I am a 48yr old women who ha s used meth introveniously and think i have gotten a sort of internal infection from the needle not being sterile because my left forearm and hand not so much. fingers hasbecome swollen and itchy painful and has persisted now for a day. Seeming like an intetnal infection .i have stopped using meth introveniously. Please advise .... Also i have started to take cephalexin that i had left over from something previous.knowing it is a good antibiotic.not wanting to go to hospital and not wanting to be judged. What should i do .?