You have to find out your schools
policy. For our school, we are allowed to assist the nurses if the professor isn't there such as (for wound care) hold the patient, hand the nurse the materials, hold the patient's hand. But we are not allowed to actually touch the wound without the teacher there. So find out what your school's policy is. As for documentation, us student's have our own documentation we write that goes into the chart that gets signed off by our teacher every night. If your nurse did her own documentation and you just reminded her of some things she missed, then that is fine. If you did your own documentation and your teacher didn't sign off on it, then that's a problem because you are not an RN, and you're not allowed to document anything without a teacher who is an RN sign off on it. But these are policies that your school should have gone over with you before clinical. If they did not go over the policies with you before clinical, then that is their wrongdoing. Your school technically should have handed out a rule book, and if they have then it was your responsibility to read it.
Remember, you are a student nurse and will be making mistakes. You did nothing to jeopardize the life of your patient. And just make sure to think about if you're allowed to do something next time you jump in. Good luck with the rest of nursing school
and I hope everything works out!