I found this on the net.
The effects of chipping off a piece of the actual core
of the inductor will vary according to what circuit it's
used in and how much chipped off, and if it's really
part of the core or just part of the packaging.
If it's just packaging, it wont bother it at all except
maybe paint it with some nail polish or something.
If it's part of the actual core, the effect of removing
part of the core (the chip) is to reduce the area, which
means the inductor saturates more easily and the inductance
goes down. The amount of this change goes with how much
area was lost -- a little area changes it a little while
a lot of area changes it a lot. Also, if it goes all the
way through (a crack) it may reduce inductance quite a bit.
Unfortunately, without knowing what circuit is being used
and what value of inductance is and the actual construction
and how much chipped off it's very difficult to assess the
damage, either immediate or long term.
One thing you could do is super glue the piece back
where it came from, if that's possible. That would
mean you've put back part of the core area.
You can also check for excessive heat rise while it's
running full steam. Check various components as well as
the inductor itself.
If the flashlight is still running and it appears to be
about the same brightness there's a good chance nothing
was hurt. The effects i talked about above could all
reduce or increase current to the LED, so if the brightness
seems the same it's probably working either the same or
almost the same as it was.
