Thanks to a graduate from my church, who's great knowledge led me to look up the makeup of a pencil more carefully after some discussion about flesh marks of the past during church lunch. Thanks to this article, I am less worry about the dark mark on my right pinky.
There couldn't be lead poisoning, since the leads of pencils today are made of graphite (carbon) instead of lead (Pb).
Some interesting history about graphite and lead as writing tool.
Since both graphite and lead were used in ancient times, the yet to be identified graphite was being tought as "black lead or plumbago".
In 1779, Swedish chemist Carl W. Scheele determined that black lead was actually a form of carbon; in 1789, German geologist Abraham G. Werner reportedly gave it the name graphite, after the Greek graphein, meaning "to write.". Inks were already widely available and were usually applied to paper with a brush called a peniculus, which is Latin for "little tail", hence the basis for the word "pencil." -- Steve Ritter
Now graphite is mixed with clay at high temperature about 1000 Celsius, to produce smoothness and hardness.