I know how you feel, I come from a long line of thumb suckers, my parents tried for years to get me to stop. My middle daughter sucked her thumb till she was 12. We took her to the dentist as this was affecting her teeth and she had a slight overbite. The dentist refused to give her braces until she stopped sucking her thumb. He made a plate that fitted into the roof of her mouth (can be taken out for eating) that she had to wear and every time she put her thumb in her mouth it would prick her gum, not painful just irritating and she stopped after two months. Of course she has to WANT to stop as there was nothing stopping her from just not putting the brace in her mouth. But it worked for us.