the butterflies he felt

The winner of the TV program "Britain's Got Talent" in 2007, Potts recalls the butterflies he felt in the lead-up to his audition.

have/get butterflies (in your stomach) informal to feel very nervous before doing something

lead-up /ˈliːd ʌp/ n [singular]
the things that are done in the time before an important event

But just like Boyle, he blew everybody's socks off when he opened his mouth to sing -- in his case, Puccini's "Nessun Dorma."

knock/blow sb's socks off also knock sb dead

spoken to surprise and please someone by being very impressive

if you give someone a makeover, you make them look more attractive by giving them new clothes, a new hair style etc

Much fuss has been made about Susan Boyle's appearance and whether or not she should have a makeover. How do you feel about that?

camaraderie--- feeling of friendship that a group of people have, especially when they work together

Just the camaraderie of the people I worked with.

have any of those bullies come out of the woodwork and tried to contact you?

come out of the woodwork
to appear or emerge as though out of nowhere, frequently in large numbers or quantity