Let’s face it, this happens to every tube of mascara over time. The problem is it dries out and then starts to form unattractive lumps. To help prevent this, don’t pump your mascara trying to get more on your wand; you’re basically pumping air into the tube causing it to dry out even faster.
Although mascara should be replaced every 3 to 4 months, I use to replace mine much sooner just because it dries out so fast and creates undesirable results. But, there’s an easy fix for that! Add a drop or two of Visine (or any brand of Eye Drops) into the tube, and then rub the wand around inside. The Visine softens the mascara liquid, making it apply as if it were a brand new tube!