Why do you thing it was a mistake to be honest. Are you concerned about being honest or by her reactions.
Your actions cannot be reactionary or you will forever doubt yourself
Can you clarify why you believe this may have been the wrong thing to do.?
I am concerned about her reaction. The last time she went away, when I told her that I missed her, she felt engulfed and she pulled away. It was okay for her to tell me that she misses me but not the other way around.
Did not hear back from her yet.
Dont worry about what is fair or apparent one sided behavior. That is life with BPD, it is an unwinnable issue.
Your actions need to be based on what you think is right, taking other people into consideration. If you say or do something that gets a poor reaction then dont beat yourself over it. If it was important to you to do or say something then do it. If it is not important then let it slide.
As a general guide when dealing with a pwBPD you will get it wrong a lot of the time (even if it was actually right, if you know what I mean )
When you are pulled up for "doing the wrong thing" let it wash, dont get drawn into Justifying, defending and over explaining, otherwise it will just escalate into something else and go off topic.
Otherwise your entire behavior will be retrained to parrot the other person. The goal posts will keep moving and you will loose yourself