Welcome to our family. You have certainly come to the right place for support and understanding.
Your car accident would certainly cause a flare of your fibro symptoms. The thing is though, have you been checked for whiplash in connection with your jaw, neck and back? If not, I would suggest that this be done asap. These are three places that I suffered dreadful whiplash with when I was rear ended. Please do go and see about this.
Any trauma like the one you talk of can cause inflammation and this in turn will make your body go into flares of muscle soreness and burning. Make sure you take any given medications regularly, and try if you can to rest and take care of yourself until you feel more able to be a little active. Did you actually go to the ER after the accident? If not, go as soon as you can because you need to be checked over properly.
Running a fever is not good, and this again is something you should check on. Swollen glands under the arms isn't something I can comment on as I really can't diagnose in any way. Think of it though, you have suffered a major trauma to your body. You do need to get checked out. If you leave things, you can run the risk of serious problems arising.
Take care and let us know how you go on.