Hello @BeckiCovington
Thank you for contacting the Instructure Community. We're sorry to hear you've been experiencing issues with regrading your quiz. Based on your explanation, it sounds like it is a New Quiz. There are regrading differences between classic and new but you can regrade New Quizzes by following this guide:
https://community.canvaslms.com/t5/Instructor-Guide/How-do-I-regrade-a-quiz-question-in-New-Quizzes/...
However, it will not always be the best solution and you will find others in the community looking for new implementations to improve the process. This thread has some good suggestions:
https://community.canvaslms.com/t5/Idea-Conversations/Regrade-New-Quizzes/idi-p/409710
If you changed the overall point value for the quiz and not the individual questions themselves, that can work but you may also need to adjust the students' scores as well. What did you change exactly and what isn't working? You could also consider contacting Canvas Support who can walk you through this and look at the specifics of your course and the student scores and submissions.
https://community.canvaslms.com/t5/Canvas-Basics-Guide/How-do-I-contact-Canvas-Support/ta-p/389767