I'm really sensitive to rejection, but I value criticism. I understand them as totally different (where I think maybe some people don't and then it gets yucky, and I've been there before too...or somehow criticism attached to my own feelings of shaming and self-hatred, all compounded like that).
Anyway, I appreciate criticism, especially when done thoughtfully or given from someone I respect and in a way that invites something like "let's brainstorm this" (problem, challenge, whatever it is). If anything I'm just working on boundaries....I've been sick a lot, am behind in some ways, and have had one colleague feel more bothered by some little aspects of my work...more bothered than I am. I typically appreciate her feedback or criticism. But after making the same criticism a few times, because I wasn't able to change fast enough for her, I just sort of shut that down by saying, "I know...I'm trying" and moved along to something else. Haven't heard any more on that. In that case it was maybe her own perfectionism...even if a critique that could be helpful, there wasn't any acknowledgement of small improvement or efforts. So just settle down please! Anyway, CBT wasn't too helpful but probably I got some stuff from my zen years. But more than thinking I'm stuck with emotional regulation and body symptoms (sympathetic hyper-arousal junk), which I think we are simply beginning to research. Then again, when I was most self-destructive, some criticism probably easily fed into my "I'm a failure" stuff. I think I've gotten beyond all that (maybe that was CBT...I don't know), now have to shift stuff on the body-trauma level and I wish my thoughts mattered more, because they are usually pretty affirming or at least patient (and even when melting down I seem to have some bit of awareness that I am in fact melting down, and that colors everything). But keeps me going I suppose, not wrecking relationships.
The criticism from valued relationships helps me grow. Sometimes I have to step back a bit to ingest it, but if I'm not sure I agree it usually helps to try to view the situation from the other person's perspective, and then forge some kind of middle ground response if needed.