I can relate here.. This can just be a lymphatic response as well as Test ester building and a positive medium in the blood..
I've been a Test E guy for most my life, recently I introduced Sust back into my life and experienced Test flue like symptoms.. I been utilizing the sust 3 x a week now, but after 2 weeks into my blast all symptoms came full swing..I took some antihistamine prescribed medication (vistaril) and all symptoms subsided almost instantly (a little more than an 1hr). I swear by this protocol to help assist with localized site issues or even flue like symptoms
Tell your buddy to get some antihistamines it will help combat any localized immune response from any invading bodies (testosterone,solvents,carriers and other residues that may linger inside the compound)..
Changing sites can have this effect due to the mapping system/lymphatic system not being familiarized with the injections.. I would suggest that he tries small volume/mL with his new injection sites, allow the localized region/tissue to react accordingly , because there will be a response in some sensitive individual's. Allow the area ample time to respond and metabolize the injection, by overwhelming the area with larger volume that he may be used to in other areas may end up being more detrimental, yielding a considerable site reaction. It's almost like an allergic reaction, WBC levels will go up, immune system may/will become compromised, having an ill effect with other symptoms alike..