There are doctors who further amplify your fear of a dentist by performing precarious work. They can do the local anesthesia incorrectly and you can feel all the pain. Moreover, they can use inferior materials at a high price in the process of treating caries.
You have to tell your dentist if you see or feel something strange, because it may cause you serious infections that will cost you your health, not just a lot of money. If you feel cheated in any way, you can contact the American Dental Association (ADA).