Fibro is extremely difficult for teens. They want to fit in so badly and you know how cruel some kids can be. I hope he has a special friend or two that he can talk to.
I did look up the side effects of Paxil and it can cause confusion, decreased concentration and this should be reported to your doctor. It might not be the medication for him. I take no medications like that. Here is a link about the side effects of Paxil.
http://www.drugs.com/sfx/paxil-side-effects.html
The only prescription med I take for fibro is a muscle relaxer called Robaxin and I have no side effect with it...except for the very first pill I took. That one pill made me sleepy. After that, no problem. I also use ibuprofen with food, extra strength Tylenol, malic acid/magnesium supplements and vitamin D3 supplements to help with pain and fatigue. I also use an alternative pain product called Curamin.
Fibromyalgia can cause something we call Fibro Fog. I find if I stress over that, then my memory is worse. But, if I laugh off my mistakes, I relax and do far better. I know that is difficult for a teen to do, but being angry is just making things worse...his pain and his memory. Stress is very bad for him.
Walking is a wonderful exercise for fibro and a real stress-buster, too. Swimming and yoga are other good exercises. He needs to keep getting involved in things. This takes his focus off his health and the pain will fade somewhat in the background.
Keeping a positive outlook has helped me about as much as medication. Fibro waxes and wanes so if he is having a lousy day, he could feel much better the next day. He really has far more blessings than problems but, at that age, it's hard to get them to realize this. He's blessed to have family standing behind him and trying to help, too.
Be sure to read Fibro 101...the second thread on the forum. See if your son will read it too. There are links to good info about fibro and you both will learn a lot there.
See if he would like to come on the forum and ask questions. We have had teens on here before. Let him know that he can have a full and enjoyable life with fibro, too. I have. I have done so many things I never thought I could do with this illness but I try everything and 95% of the time, I can do it. I've traveled overseas several times, done activities like parasailing, swimming with dolphins, snorkling, etc. I have a good life but so many times people think their lives are over when they get this diagnosis. Once he finds what helps control the pain, he should do just fine.
Sherrine