Like neveline*, he , after Hermoine immobilized him, ....didn't he told Dumbledore what happened?....I can't remember.
Anyway, what do you think?
PS: 12321, Neo
- yeeeah, Mint has a bad memory, nothing new
, you don't have to say it again and again and again 

Anyway, what you have all been saying is true: some spells, like those mentioned, will wear off, but curses are more likely to be those that need to be countered with another spell before wearing off. (Harry's bones didn't grow back by just sitting around doing nothing, now did they?)