Cannot say in dermatologic conditions without seeing them, but can give general information. Some common causes of skin conditions after heroin injection are capillary leak (very minor problem but the red dots often never go away and just become brown dots over months/years), plain bruise (more often goes away), infection (usually with worsening problems like redness/warmth/pus/ spreading redness/ red streaking) that is serious and needs treatment, Skin / tissue death from bad stuff in the heroin (the area can further break down and is usually really REALLY painful, clots, first, note that the if the clot breaks off and does go to the lung the area of the lung affected is based on the size of the clot. If it is the size of a regular arm vein (pea sized) it s unlikely to cause a noticeable problem and often helps the arm circulation. If the whole arm swells up due to a clot involving the length of the vein going down the whole arm then this is a clot that could be fatal. It would be noticeable as a very serious circulation problem before it broke off. If someone isn t commenting on the whole arm swelling up like a balloon and usually also changing color to that of an eggplant, a serious clot is just not likely, one can have an allergic reaction to the tournequet. It is 1) like an allergy.. itchy, hives, etc. 2) goes away like an allergy 3) comes back with any latex exposure and 4) actually potentially deadly.. .but only if you get latex INSIDE you like surgical gloves during surgery if you have a latex allergy is quite serious. So.... infection or more likely just capillary breakdown. Doesn t get worse in hours/day or gets worse then needs attention immediately.