I told a plan b but it dissolved in my mouth i got it all down with water will it work or do i need another one ?

Plan B contains high concentrations of two hormones that interfere with ovulation and the implantation of a fertilized egg. As long as you swallowed the pill (dissolved or not) the hormones were able to get into your system. Remember that Plan B is a backup. You should be using some other form of birth control regularly. High levels of hormones taken frequently can cause many side effects.