Can you use obverse/reverse when referring to a sheet of paper?

Obverse:

• The side of a coin or medal bearing the head or principal design.

• The opposite or counterpart of a fact or truth:

Reverse:

• left-hand page of an open book, or the back of a loose document.

• The side of a coin or medal bearing the value or secondary design.

Source: Oxfordictionaries.com

While reverse may be used to refer to the back of sheet of paper, leaflet or document, obverse is not used with that meaning, but it refers mainly to the side of a coin, paper money or drawings (with reverse as its opposite with that respect).

As suggested front and back are more appropriate terms for common usage regarding a sheet of paper.

I would simply say "on both sides" or "front and back."

Please fill out this form (front and back).

Please fill out this form on both sides.

If the paper has been written on both sides it is called a opisthograph but wrong side of paper is the Wire Side or the "Opposite of felt side, this is the side of the paper that was against the wire during manufacture. A watermark will read backward from this side of the sheet."