(D) Dismissible
If the duration line ends with “(D),” you can dismiss the spell at will. You must be within range of the spell’s effect and must speak words of dismissal, which are usually a modified form of the spell’s verbal component. If the spell has no verbal component, you can dismiss the effect with a gesture. Dismissing a spell is a standard action that does not provoke attacks of opportunity.
A spell that depends on concentration is dismissible by its very nature, and dismissing it does not take an action, since all you have to do to end the spell is to stop concentrating on your turn.
Mask From Divination
School divination; Level alchemist 5, bloodrager 4, magus 5, shaman 5, sorcerer/wizard 5, witch 5
CASTING
Casting Time 1 standard action
Components V, S, F (an eyeless mask), M (diamond dust worth 200 gp)EFFECT
Range touch
Target creature touched
Duration 24 hours
Saving Throw Will negates (harmless, object); Spell Resistance yes (harmless, object)DESCRIPTION
As part of the action used to cast this spell, you place the mask used as the focus component on the target’s face, after which it adheres tightly to the target for the spell’s duration and cannot be removed by physical force. Despite lacking eyes, this mask does not impair its wearer’s vision in any way. While in effect, this spell functions like nondetection, except it also foils divination spells that attempt to gather information about the creature, even if they don’t target it specifically. In the case of divination spells that would normally reveal the wearer’s presence, such as see invisibility, the spell works, but the wearer is detected only if the caster succeeds at a caster level check. Likewise, scrying attempts that specifically target the wearer do not work at all unless the caster succeeds at a caster level check. In addition, the DCs of skill checks to learn about the wearer or identify the wearer and its strengths and weaknesses-including Diplomacy checks to gather information, Perception checks opposed by the target’s Disguise checks, and Knowledge checks-increase by 4.
The mask cannot be removed for the duration of the spell, and the fact that the target is wearing the focus mask cannot be hidden in any way from creatures that observe the target.
The spell isn't dismissible and you cannot remove the Mask for the duration of the spell, so if you really want to end the spell, you could Dispel yourself.
Per Dispel Magic, you auto-succeed on dispelling any spell you cast yourself.
Glad to help ;)