Once you use psychs a lot, well at least for me, your perception of "time" becomes so altered a "bad trip" doesn't have much ties with the present. Like the past, present and future are no longer this simply linear relationship so a bad trip wont really effect you that much, it will be somewhat akin to a nightmare that u barely remember, you will know you had a bad experience but it's just an experience with no real negative emotion attached to it, viewed from ur present perspective. I've had around 30 - 40 shroom trips, around 100 DMT trips, around 5 proper salvia trips and 100s of weed trips(i'm VERY sensitive to weed so its very psychedelic to me). I've only had one real bad trip so far, which was my first, and on weed. The rest I would say have been negative, but not necessarily a bad trip, though that could be because my bad weed trip was so bad none of my other negative experiences can match my perception of a bad trip.
My bad weed trip was 4 hours long, it started with me turning into a worm and thinking this is how u leave ur life...smoke weed turn into a worm and feel great! then i left my body and went into this astral plane, seeing many people across the world taking high doses of psychs and entering the same realm i was at, then I was suddenly slammed back into my body and what followed for the rest of the 4 hours was fear so intense anytime i dared open my eyes or perform conscious movements like breathing, a level of fear akin to knowing you were about to die a painful, certain death, was bestowed upon to me. The worst part was that time was ridiculously dilated, after 3 mins I thought the weed trip was already over, usually i would trip on weed for around 4 hours, I really felt like in 3 minutes 4 hours worth of experience had passed.I could literally write like 5 books on how hellish the experience was, that much negative shit happened, that to me is a real bad trip. Time is so elongated it feels you have been there for many lifetimes, every moment of existence is pure terror, there is absolutely no escape, everything is against you, even the air you are breathing. Such experiences to my understanding are rare and usually only occur when ingesting unexpectedly high doses of a pcyhe.
With my shroom and DMT trips the negative experiences i've had usually leave me with a lesson, as for salvia, i'm too disconnected from my emotions to feel true fear, so it's most like i'm just observing fear. I've had only 2 negative shroom trips, the 1st made me realize the bullshit within myself, at the time i fooled myself into thinking I was using psychs to achieve enlightenment or something, but really I just used them because they were interesting and most importantly, felt good. Once I realized that my shroom trip got much more euphoric, same with DMT. With DMT i've only had about 3 negative experiences, all of which I account to unexpectedly intense experiences. I always measure my doses but sometimes they are more intense, recently I found out that it's most likely due to a build up of DMT resin in my pipe.
Another thing i notice is that anytime I have a negative experience the next negative experience is less intense(emotionally speaking), I think as time progresses and depending on how you rationalize things, you eventually get use to it, and a bad trip is no longer something you fear, just an annoyance that will usually teach you something about urself. I believe the psychedelic experience has VERY strong ties with your subconscious mind, heck if not for my DMT experiences I'd believe it was all in your mind but some of the experiences i've had seem far to alien to exist solely in my mind. The way I see it, a bad trip is inner-conflict between your sub-consciousness so if you analyze your bad trips properly you find there is usually a reason it happened. More inner peace = less bad trips. There are various of ways to get more inner peace within ur mind, meditating works well, another is to bring up all your issues and fears, regardless of how trivial, and deal with them.
