That happened to my son when he was a younger teen. And, his liver was enlarged. Yes, it is scary. What they did was wait for 3 months, check his bloodwork again, and palpate his liver every time we went in for anything.
It turned out that by the next time we checked his bloodwork, nothing was wrong. And his liver never felt swollen after the initial time.
We found this accidentally when he had a staph infection from a cut on his knee that was infected. We didn't even realize it, because it didn't hurt him. What hurt were the lymph nodes in his GROIN, big time! Swollen and painful. Turns out that the infection from his knee cut caused the lymph nodes to work overtime to fight the infection. The doc put him on some strong antibiotics to beat the infection.
The doctor told us that he couldn't imagine that the liver and the infection/lymph node issue had anything to do with each other. Far be it from me to question that, since I'm not a doctor, but there has never been another time that there were any liver problems before or since.
Anyway, I would talk to your son about this and ask for a "head to toe" exam to rule something like this out.
Good luck, S..
Dawn
The doc s