Because you fear hurting your friend, it shows that you care about her and that you regret hurting her before. Friendship needs honesty, so let that guide your actions. Maybe the first thing you say when you start talking to her again is that you're sorry and that you regret hurting her. You can tell her you're not perfect and make mistakes, so you fear hurting her again, but also that, even if you do hurt her, it doesn't mean you don't care. You can even ask her to help you out by telling you what exactly hurts her, so you learn from your mistakes.

See, regrets can be burdens you carry around that make you fear every action, or they can be lessons that you learn and grow from. You won't have as much reason to be afraid if you know what you did and how to avoid it and she can help you discover that and you can both grow together through friendsip. It all starts with an apology and being honest about your feelings, including your fears.

I hope you two can work things out. :)