When you have a sore throat from smoking cannabis, the first thing you should do is to stop smoking cannabis to ease some of the pressure on your throat. Next is to find an alternative means of getting the cannabis fix such as vaping, topicals, or eating edibles if you surely must have it. But you could also just wait until you are fine before getting cannabis again, this is because some people would rather do that rather than use the alternative means. After that issue has been sorted out, you can then treat your sore throat with any of the under-listed methods.