1. Rash is a collective noun and is not used in the plural unless you are talking about more than one person. "He had a rash on his hands, feet and buttocks."
2. Gotta is colloquial for got to which includes the infinitival to which requires the infinitive form of the verb [to] find.
3. Re-ignite means to light (ignite) again.
4. twenty-twenty, one and a quarter, two squared, eleven cubed, three is loess than four, five is greater than two, square root of nine.
5. Adolescents can't give each other the first two diseases (they are not contagious) because they think that love protects them. They also think that love will protect them from AIDS.