Are you wearing your jaw brace at night? If you haven't done for some time I suggest you go and get fitted for another and talk to the dentist about this. If you've worn it within the last couple of weeks and it fits fine then if you've not been wearing it regularly you can try with this for a few days and see if that improves it. The joint where your jaw attaches to your skull (your tempero-mandibular joint (referred to as TMJ)) is close to your ear so that is why you can hear it popping. Also, try to eat soft foods for the next few days and don't chew on gum or sweets and see if that helps because it may be you've pulled a muscle a bit. Though it does need to be checked out by either a dentist or doctor if you are still having problems with it in a week or if it is worsening. I'd also see them to be moulded for a new plate if you haven't used it for some time; don't use it if it has been a while as the shape of your jaw may have altered a bit and it can cause more damage.
Are there any reasons why you have suddenly started purging as that in itself is very dangerous and won't help with this. It may be worth getting support for the emotions behind this by writing a thread or contacting the Supporters via "Live Help" or emailing them
support@recoveryourlife.com.