One thing I am thinking about is if it is raw honey, there could be bacterias in there. But they are not able to grow to more than a small number on the honey because it is a very difficult environment for them to live, for multiple reasons. There is too much sugar too densely together that is not good for them. Actually having a very high amount of sugar is used as a preservative for this reason, like a jar of jelly.
Then when you dissolve it in warm water. You are creating the perfect place for the bacterias to live. They can live in the water and eat the sugar. And if you left this for a few days, you would have a very high amount of bacteria colonies in such large amounts that you might see large solid pieces of them. And if the bacteria did not originally come from the honey, a lot more types would come from the air and land in there.
So this would make you very sick or maybe be deadly if you left it for some days. But making it then drinking it very soon after, like some people do with tea, is completely harmless.