I believe I had this problem on both Oblivion and Fallout 3, but for the life of me I can't figure out what I did to restore my lockpick back to 100. I have dozens of bobby pins, so it's not that, and in the level up menu my lockpick is clearly at level 100. Help, anyone?
Are you addicted to drugs, suffering from a sickness (if in hardcoe Mode) or wearing an item that would effect the relevant stats?
Check your stats, both SPECIAL and Skills. There would be a (-) next to it if you are.