I usually ride my horse in a tom thumb bit but she was fighting with it today, which she never does. My instructor looked at her mouth and said she had a bump on her gum that looked raw. So she switched me to a hackamore. She didn't fight it but I had much less control of her. I think this helped to contribute to my fall today. What can I do to gain more control. I almost ran over a three year old at the canter because I couldn't get her to stop or turn. Help before someone gets hurt.