Supposed to be posted a few days ago:
Would it be safe to say that you overdid it, somewhat...?
It started off sounding quite nice, but it escalated into something rather horrific.
That's precisely the issue; the extreme negative side effects occurred in tandem with the above positive side. If they occurred merely on the comedown I wouldn't mind as much. Most stims have a line at which the negatives outweigh the positives, 3-FPM quite simply doesn't.
An overdose which is enjoyable is not typical of any drug I can think of.
I've pretty sure that if the incredible amnesia (a decent indicator of neurotoxicity) was not present, I'd hate the experience. If a negative cause-effect relationship can't be established, the positives seem magnified.
Also, forgetting completely that you dosed just 5 minutes prior along with the ubiquitous fiending makes for a massive chance of acute overdose.
The reduced sensation in the limbs could quite easily lead to the dangerous effects of long term vasoconstriction, and subsequent cardiotoxicity wayyyy before they become subjectively apparent.
Recurrent paresthesia is another solid indicator of potential toxicity.
There were/are many more issues than above, not least the worry of the 5-ht2b agonism associated with substitutions at C3 as seen in the Amphetamine (3-F/MA) and Cathinone (3-MMC, 3-FMC) families. The structural similarities are enough for me to consider the likelihood until further notice.
My biggest concern is the metabolites - I have a feeling some are active and differ massively from 3-FPM (SRI/SRA?). Any action on MAO in addition could be fatal.