WUNDER2 SUPER-STAY LINER Long-Lasting & Waterproof Colored Eyeliner, Essential Navy Blue

Can this liner be used on the inside of the lower lid?

Where can I buy a Wunder sharpener?

I have very oily skin, has anyone tried to see if oil smears it?

Any tips for sharpening? It seems like the wood is unusually thick and my sharpener cant sharpen it smoothly, it chops it up