Drugs stay in body and can come back to the blood system when stressed.

[mikemeas]

Wie lange verbleiben Drogen im Körper? - Teil 7 - YouTube

This is basically an austrian national site where they talk about drugs and how long they stay in the body after usage. They say the drug can deposit in the fat tissue and since fat is burned when stressed or something the deposited drug can get back to the blood flow and yes, they say the drug can impact the perception and stuff. I always believed the drugs just caused some irreversible damage in the "perception"-areas and it just be like that for now on, but this is a new information I didnt know before. No cure but I found it interesting to share. So maybe my HPPD is just because the acid or THC (which needs years to extinct from the body) is still in my body. If thats the case, it just makes it even more important to stay away from drugs I think.