Lev pen suddenly just empty, dried up

Yesterday there was Levemir insulin in the blue pen and today I pulled it out of the frig, out of paper towel piece I wrap it in, out of plastic storage bag, and saw nothing wrong. Then I took the cap off, inserted syringe, drew and there was nothing in it. Just air. So in the pen the little bobber piece went back and forth and there was no insulin in the pen. So, where did the insulin go? It hadn't leaked into the paper towel or plastic bag. And it was close to full. Has anybody else ever had this happen?

And, are you keeping your Lev pen in the frig between using it? I have been even though instructions say otherwise. Thanks from Emmy, Mabel, Ady

 

I keep mine in the refrigerator. (I do not wrap in anything or put in anything, it just lays on the shelf.)

Disappearing insulin is weird! Does it evaporate if spilled? Maybe it leaked/spilled somehow but completely evaporated so you cannot tell?

 

Last night how close was the orange moveable rubber stopper close to the place where you insert the syringe needle?
Where was it this morning?
I have been using pens for more that 10 years and always store in fridge with no problem