In the pathfinder society,could i use‘mask of conflicting’ If i am not the believer of Nethys?

[Ilica]

We can know that the mask do not need its user must believe Nethys.
However,it says that ‘ As a general guideline, if a character receives any mechanical benefit connected to a deity, that character must worship the appropriate deity.’in PFS Guild Guide.
I do not know if my role can use it with no faith of Nethys ......

[Starglim]

The mask has no special effect for a worshipper of Nethys and Additional Resources doesn't require you to be a worshipper of Nethys to buy or use it.

[James Risner]

Ilica, why do you think it's a Nethys item?

[Nefreet]

The Original Poster likely read the description and understandably believed it was a Nethys-themed item:

Mask of Conflicting Energies wrote:

This mask is white on one side and black on the other, with glittering gem lenses covering the eyes. Up to three times per day, the wearer can change the energy damage of a fire spell she casts to cold, a cold spell to fire, an acid spell to electricity, or an electricity spell to acid. All other effects of the spell are unchanged (for example, an ice storm changed to fire damage still deals bludgeoning damage and bestows a penalty on Perception checks). The mask affects only spells up to 3rd level.

But, description aside, there is no requirement included to actually "worship" Nethys. You'd be fine with just mundane "veneration".

[Starglim]

Nefreet wrote:

But, description aside, there is no requirement included to actually "worship" Nethys. You'd be fine with just mundane "veneration".

Casting lots of fire, cold, acid and electricity spells will also make Nethys happy.