I agree with nicole and vibe. But I would call it a slip. If you catch it now you wont slide into a complete relapse where it is a behavior you are doing to relieve stress. Call your T. I know that you said that you were only seeing her maybe every other week, but this is something she needs to know about to help you. Also tell your parents. You need all the support you can get to keep this from getting worse. In coming here and asking it sounds like you want to keep this from getting worse. That is a good thing. Take the next step and get help IRL. Try to figure out what it was you were feeling or thinking or doing before you cut to lead you to use that as a release. It is important to find the trigger so that you can work on it and work on your coping skills.

This does not make you a bad person. It means that you need more support right now. It doesn't mean that you will return your previous behavior. Take care of yourself.