Finger Pads
The soft, squishy, fleshy underbelly of the fingertip underneath the fingernail — the finger pad — is not normally the first target of for a compulsive finger picker. Even through the nastiest bouts of compulsive picking of the cuticles, nail folds and other skin around the fingers and hands — the finger pads usually are left alone and retain their soft fleshiness.
Some skin diseases such as acute Exfoliative Keratolysis can cause the finger pads to peel, as well as other fleshy, non-calloused parts of the hand such as the palms. Also, manual, hand-intensive labor that cause calluses — such as guitar playing, drumming, lathe-operating etc. — can create a skin texture rough enough to tempt someone to start picking at it.
Some other odd parts of the fingers: