I'm sure it's been written about 100 times but I cannot find the exact answer to my problem, so iv just been to the needle exchange and she asks are the injection sites ok? I say yeah but the skin is getting a bit tough to stick the pin in, off she runs to get help, and then I get a dumbass lecture, but does she have a point ? Scar tissue build up and will it dissipate naturally ? I pin glutes, lats, quads delts, but I always pin in nearly the same place