Sorry to hear about your bad experience. Your twists look nice. One thing to remember is that you're paying her to do a job. If you feel uncomfortable about anything she's doing to your hair, speak up. She has to listen to you. The lighter over the hair would freak me out, so I don't blame you for being upset. Next time you get your hair done, let them know when their technique is NOT acceptable to you. It'll save you the worry in the long run.