User bought (4) boxes of mm 31g x 8mm pen needles with lot no.Y46zc2.He injects 5-10 units of humalog on a sliding scale 1x per day with the corresponding pen.He called because his pn is breaking inside the pen somehow.This has happened several times.Wife was able to push one pn tip out of the pen by pressing really hard but, the others could not be removed which makes the actual pen useless.