<P> Permanent vein collapse occurs as a consequence of: </P> <Ul> <Li> Long - term injecting </Li> <Li> Repeated injections, especially with blunt needles </Li> <Li> Poor technique </Li> <Li> Injection of substances which irritate the veins; in particular, injection of liquid methadone intended for oral use . </Li> </Ul> <Li> Long - term injecting </Li> <Li> Repeated injections, especially with blunt needles </Li>

How do you know if you collapse a vein