Psychologyist does not ascribe labels, will this help me?

OK, so firstly I am a self diagnosed bpd, and I have only been seeing a psychologist for a couple of sessions. I have set aside some time for the upcoming 12 months to get in a good place and develope the strength to deal with my rapid mood swings and all the things that go with it. The person I am seeing uses a humane approach, patient centered, based on the idea that they know there own mind best, too understand their position and support them with their decisions. This is good, I like the idea of this. But I know what I am like and what I do. I often under represent the feelings I have felt when I need to fill out one of those questionnaires at the beginning of the session. I have not told either my consultant or psychologist about my self harm, albeit on the off occasion. I can sit in a therapy session and mislead, watching myself do it and not be able to stop myself. I feel guilty though, this line of therapy is not there to extremely probe or trick me, but I find myself treating the sessions still with suspicion. Because there is no attempt to use labels, the experiences I describe are treated as healthy reaction to something rather then a sign of a disorder. I fear that I will be trusted too much and I will find it easy to manipulate the situation.
I am not sure what I am trying to express here really, only my experiences or fears. I was just wondering if anyone can offer any advice on how to approach therapy. I want to maximize the oncoming year to get better. But I am afraid it will be like all those other times I reject any form of therapy within a couple of months.

Write down what you're doing (or just print off your post) and hand it to your psychologist next time you see him/her. That way, at least your psychologist will be aware of what you're doing (if they aren't already) and can focus on that, too.

I agree with Johnny.
Your psychologist believes that you know you best, so they should be very open to hearing the issues you've posted about. By telling you psych about these, you will be able to work past them with the help of your psych and make much more progress this way..
I know.. its hard... I am still working on being completely open with my therapists about these sorts of things.. but they always encourage me to do so.