It’s possible for nerve damage to occur without any warning/symptoms at all, and even with an experienced top who does “everything right.”
Generally, the type of bondage pain that is going to cause long term damage is a type of pain that will set off alarm bells in the bottom’s head. It will not feel erotic, it will just hurt! Bottoms must also be alert to numbness and tingling (which also doesn’t feel erotic to most people), not just to sharp shooting pain. If you’ve ever hit your “funny bone” then you know where your ulnar nerve is and how it feels to have trauma to it- not sexy for anyone I know.
Sometimes nerve damage may be focused on a particular area rather than the entire limb. For example, the ulnar nerve covers, among other areas, the pinky and half of the ring finger. So, if a bottom reports numbness and tingling only in a specific “zone” rather than an entire limb, that’s a good clue that the symptoms are due to nerve compression. HOWEVER the fact that the entire limb is numb/tingling should not be taken to mean that the damage is NOT due to nerve damage.
Several very experienced bondage bottoms have told me that they can tell there is an issue with their radial nerve because the top of their thumb goes numb. They therefore monitor for this during a scene by rubbing their index finger on the top of their thumb periodically to make sure they can feel it.
Even “minor” nerve damage can have major consequences. A relatively mild injury to the radial nerve, if on the bottom’s dominant arm, can easily render them unable to write or type for days or weeks – a major problem for most people.