A few years ago I did a quad injection where I think I hit a lymph node. My leg swelled up like crazy, couldn't see my kneecap. Was painful to bend my leg or walk, I felt tired all the time, too. But like your friend, no hotness or fever.
The swelling took over 2 weeks to go down and I was back to normal after about 3 weeks. I suggest if the swelling doesn't go down after 2 weeks to visit a doc. I heard about a guy who had the same thing happen to his leg as me and had to have it drained. All the best to your friend.
