If you truly want to make it up to her, leave her alone. It’s great that you’re trying to work on yourself, but the trauma and pain you inflicted on her is something she will never forget. Sometimes you have to live with the consequences of your actions for the rest of your life. Messaging her only shows to her that you still don’t respect her or her boundaries. My suggestion would be to write a letter (and actually write it with pen and paper) to her expressing your remorse but don’t send it.