Curious

[Liz0911]

Can someone explain please..on the  One Cent?

[Just Bob]

It looks like a plating bubble. I assume that is also what is going on next to his mouth, on the obverse, as well.

[Greenstang]

Agree-

When the bubble is in a line like yours, it is known as a Linear Plating Bubble.

The weak  E CE looks like it may be caused by a partially grease filled die.

[Conder101]

It is plating bibbling, but I'm not sure I would call it "linear".  Not sure why the plating followed that curve, but it would mean there was probably some kink of curved scratch on the zinc blank.