Yes the Pentacle or Pentagram is a Pagan protection symbol. Here is a little info on it.
Traditionally four of the five points of the pentagram has been attributed to the four sacred elements: Earth, Air, Fire and Water, with the fifth
point (uppermost) representing Spirit:
Earth: Is represented by the lower left hand point of the star, and is symbolic of Stability and Physical Endurance.
Fire: Is represented by the lower right hand point of the star, and is symbolic of Courage and Daring.
Water: Is represented by the upper right hand point of the star, and is symbolic of Emotions and Intuition.
Air: Is represented by the upper left hand point of the star, and is symbolic of Intelligence and the Arts.
Spirit: Is represented by the topmost point of the star, and is symbolic of Deity the Divine, and the All that Is.
The Circle around the star represents sacred space, in which the spirit (the fifth element and top-most point of the star) controls the four earthly
elements. The four elements are also associated with the cardinal points of the compass i.e. Earth is to North, Air is to East, Fire is to South and
Water is to West, and it is to these directions that the pentagram is drawn to invoke or banish their requisite energies. Many witches use this
method to invoke the rulers of the four quarters that they may protect and watch over their proceeding (see Circle Casting).
Pentacle - A 5 pointed star surrounded by a circle. Also - A circular piece of wood, metal, clay or other material onto which a Pentagram had been
inscribed. It represents the element of Earth. Also seen in the Tarot decks. Some people call the upside down pentagram a pentagram and the right
way up one a pentacle. and some call them all pentacles. Items are placed on the pentacle during a ritual to consecrate them.
Pentagram - A 5 pointed star. Each point represents an element : Earth, Air, Fire, Water and the fifth element, Ether or Spirit. It is the symbol of
the horned God when turned upside down( nose, ears and horns make up the points). It is not the symbol of Satanism, as some believe. It is a symbol
of protection, and many Wiccans and Pagans wear one as a symbol of their religion and for protection. It can be scribed into or drawn on objects to
protect them. The upside down (inverted) version is a "banishing" pentagram, and the right way up, the "invoking" pentagram. The Pentagram was
used by many religions (including Christians) as a symbol of truth and Protection before it was said to symbolize "Evil". The symbol apparently was
used until the inquisition as a positive symbol, and then its meaning was reversed. Some say that the upright pentagram shows Spirit/Divinity being
first... it comes above everything else, and that the inverted pentagram shows Divinity at the bottom, and thus placed after ever thing else. Which
is said to be why Satanists use the inverted symbol, not because of it's associations with the devil.
I hope this helps you in some way. As far as the photo of your hand. It is very hard to to say for sure. But I kinda see what your talking about. You
might want to try google for Palmistry.