You could try your GP, but mine did nothing - and my jaw is much worse than just being “clicky”. How much is it affecting your DD’s life? Does she complete the exercises? How long has she had the symptoms? Have they progressively got worse? Is she in pain? These are all questions she’ll be asked. Also - what age is she? TMJ isn’t an uncommon condition, but it is much more prevelant in adults than children. I developed it as a young teen, but it has become progressively worse over the years.
I am now at the stage where my jaw clicks and moves every time I open and close it, it regularly locks (thankfully it only locks closed and has never locked open... yet!), and it causes me some level of pain probably at least 50% of the time, with severe pain meaning I am only able to eat soft foods about 25% of the time. (I live off soup when things are really bad and even that can be hard as opening my mouth to get the sooon in when my jaw is locked is excruciating.)
After years of it getting worse my dentist referred me to Max Fax at the hospital but waiting lists are long in my area and it took over a year to be seen. I have a night splint to wear, but it doesn’t really help - probably because my TMJ isn’t caused by teeth grinding which is what the splint is designed to stop.
I am due another appointment shortly so we’ll see what the consultant says then. There are other options - ranging from exercises to surgery. I am against having surgery if at all possible, but one route we may consider would be braces as my jaw is very misaligned and this may well help. The cost to me as an adult could well be prohibitively expensive and I don’t know what the nhs would cover.
I honestly think your best bet would be to push it with your dentist again, and if they really won’t help, then go to the GP. Dentists know more about things like TMJ than most GPs do.