i ll try to answer your question and i hope it will help you. repeated iv injection and if not done with the correct technique and hygiene can caused the possibility of infection either in blood vessels or in muscle. the usually symptoms are swelling, redness, heat, pain and fever. first aid is to compress with cold water or nacl 0,9 %. it is advisable should be checked to the doctor for further examination such as blood leukocyte examination and if necessary blood culture. these conditions sometimes must be given antibiotics through iv, other than doctors can give pain killer or maybe anti coagulants. thank you.