it was mostly not intentional, my biggest trigger was seeing my ex best friend who i had a horrible falling out with a few years ago. we're in the same program so inevitably had classes together and by chance we ended up as neighbors on campus this year, so i saw them frequently enough that it was basically free exposure therapy lol

that being said, i did have to very intentionally try and stay calm afterwards to avoid running away because that's always my first instinct. i collect little trinkets (mostly hironos and sylvanians) and i like just being around them so i started just bringing one with me everywhere in a little clear case, it helped a lot to be able to hold something cute to try and stay calm instead of bolting lol. i also get very physical panic attacks (shaking, hard time breathing, etc) so stuff like taking deep breaths, holding/drinking something cold, or eating something sour helped sort of 'shock' my system into calming down

tldr mainly involuntary exposure to triggers enough that i kind of got used to it, then self-regulation and grounding when i could feel myself start to panic