The lever is mounted on a ring of spring steel (a retaining ring) that presses
against the interior surface of the barrel. The interior of the barrel has a
groove that the retaining ring fits into. The ring needs to be re-seated into
that groove. Using long-nose pliers, or even forceps to pull the lever into
position is likely to damage the lever.
The hook in your photo is the right idea, but way too large. You need
something that is fine and strong; a dental pick. Or possibly a very small
crochet hook. And great care.
Once the hook has been inserted into the barrel and has engaged the retaining
ring you must start pulling. There will be resistance. A lot of resistance.
The end of the pick which you will be holding can, if you’re not paying
attention, press against the end of the barrel and knock out a chip.
Just to keep it complicated, you might also bend, or even break the retaining
ring. End of game.
This is real grunt work. Not difficult, but fussy.
This assumes that there is no JBar in the barrel.
If there is a JBar, you will need a pair of fine, long nose pliers to remove it.
The process of removing it might even help re-seating the retaining ring.
Again, keep an eye on the front of the barrel so that you don’t chip it.
Or you can just send the whole damn thing to Ron Zorn or Danny, wait three
months and then re-sac it.
In any case, all best with it.
Ain’t pens fun?