I believe that you are asking about the events of Chapter 27 in this question. This is part of the episode in which the king and the duke are trying to swindle the Wilks family by pretending to be their relatives from England. What Huck tells the king he saw was many of the Wilks family slaves going into and out of the room in which the king was staying. There is not really much that comes of this, other than the king and duke getting mad at one another.
Of course, what has happened is that Huck has taken the money himself. He does not like the fact that the king and duke have swindled the Wilks family. Therefore, he takes the money and intends to make sure the family gets it back. When they discover the missing money, the king and the duke come to interrogate Huck about it. They are asking him whether he has seen anyone go into the king’s room. The result is seen in this passage:
The duke says:
"Have you seen anybody else go in there?"
"No, your grace, not as I remember, I believe."
"Stop and think."
I studied awhile and see my chance; then I says:
"Well, I see the niggers go in there several times."
Both of them gave a little jump, and looked like they hadn't ever expected it, and then like they had. Then the duke says:
"What, all of them?"
"No -- leastways, not all at once -- that is, I don't think I ever see them all come out at once but just one time."
By saying this, Huck has put the blame onto the slaves. There is no danger because the king and duke have fraudulently sold the slaves and they are no longer in town. Therefore, Huck doesn’t have to worry about getting them in trouble or about being found out as a liar.
The only real result of this is that the king and duke argue. They each blame the other for the loss of the money. Eventually, the money gets back to the family by accident when the real Wilks brothers show up and the body of Peter is exhumed to help them prove who they really are. I suppose you could say that this was a result of what Huck said, but I think that is a stretch.