1- the scrotal skin is sensitive to temperature;when you feel warm it relaxes to get cold
similarly when it loses heat ti conserve heat it shrinks thus producing wrinkles
so not to worry.
2- the strong odour shows less consumption of water & more time lapsed holding urine so don't wait too long to pass urine.
3-there can be occassionally a drop remaining when you strain much during passing of stools or urine it should not be a worry .
4-sperms ejaculated can be thick or thin if the sperms is passed out after few days it can be thick or otherwise normal in consistency.
i hope you are satisfied with the answers .