She is probably drinking when she knows you are not watching her, but after 7 months, she should be used to you by now!
If her urates are white, she is drinking. If they are dark color, brown or orange, she is not drinking.
Just keep your dripper going several hours a day, and make sure it drips from the top of the cage and runs over the leaves and branches.
All chams seem to have different drinking habits.
Mine does not drink when misted, only the dripper. He will actualy put the end of the dripper (soft plastic tube) into his mouth!!
Yes, you should spray her directly (not right in the face!!) and get her dripping wet at least once a day. But you should mist 3 or 4 times a day depending on how dry and warm it is where her cage is.