We suspect he was exposed while at Scout camp two weeks ago in northern PA. He started the fever Saturday night, and as soon as he said his joints ached, I thought LD was a possibility. It's not flu season, and he didn't have congestion or intestinal problems. Since he continued with low-grade fever on Sunday, I was ready to take him to the clinic this morning in any case. When he told me this morning that he had a bump in his armpit and a rash on his side, it was a done deal. He's on Doxycycline for 10 days, following up with his regular doctor on Thursday. The clinic doctor seemed very competent, but since we have considerably more experience with LD in Pennsylvania than in SW Michigan, I'll feel better when his regular doctor reviews the situation.
Today he's feeling more peppy and keeping up his energy in the evening - perhaps due to the the ibuprofen, since it seems early for the antibiotics to be helping much yet.
FYI.... When I came down with it years ago it was with similar symptoms at 1+ weeks after being bitten. The fever and chills didn't break until day 9-of-10 of tetracyline treatment. The fever/chill cycle was rather weird and cycled every hour. I couldn't hold anything down and subsisted on ibuprofen, tetracycline and Gatoraide (electrolytes) for 12 days, losing over 20 lbs. I was worried the disease might not have been cured since there was only one day of anti-biotics beyond the fever break. Since then I've had no other symptoms or recurrences so I suppose it was enough.
Although I was infected I consider it fortunate I had pronounced symptoms early so that the initial treatment would cure it. Some people don't show symptoms until years later and then it's very difficult to get rid of. Good luck. I think your son is lucky with early symptoms and hopefully will come out of it fine.