Same as me, 3rd time id ever take acid ( Purple Ohms ) and the first time id ever had any real crazy visuals, had a kind of freak out but it passed. 8 days later, smoked a bit of weed, went to bed and felt myself 'falling' again, straight into that mental bad trip id had just over a week before - ever since then its never really gone away, well, the ripples of it anyway, the 'flash-back' lasted all night, crazy visuals, thought I was forgetting how to breath, all sorts of crazy shit - to this day the trailers are there, geometric patterns on carpets appear, even that crazy feeling in your mouth when you are tripping big time comes and goes - I actually feel like if I really tried, I could put myself back into that super heavy trip from way back in the day!!
I actually continued taking acid for another few years, usually offset with Temazepalm, pretty heavy Extacy use as we'll, some tablets with crazy trips attached to them too until I was maybe 22 or 23, then the Coke was the main thing, that I liked as it was non pschycadellic. Weirdly enough, some of the only days in wow, 28 years I've felt normal, and 'everything' was back to normal visually was when taking really good 'E', pure MDMA for example seemed to make me 'normal' again, crazy really!
Dabbled with lots of downers too, smoked some brown usually to take the edge f mad cocaine sessions, really enjoyed taking downers as life get pretty 'normal' again in those times!
Anyway, I've done no Acid for wow, 25 years, 'E' for 21 or 22, been coke and effectively Drug free for 8 years now.
Its there, it aint going away, I watched a thing the other night that linked the 'over sensitivity' to light with a kind of 'PTSD' and then the anxiety, which kinda works for me, the strange sights are what they are, the fear or falling back into that 'bad trip' is pure anxiety - I need to be stronger than my HPPD, and I think I am.
The human mind, what an amazing, and sometime scary place!