About domestic violence

WHy would your son go to jail if your husband hit you? That doesn't make sense.

I think that you would tell the police that your husband hit you, rather than who actually hit you- your son, so that your son would not be charged and sent to jail.

That would be the wrong thing to do, and I can't believe you don't know that.

Are you afraid your son would go after your husband and then be in trouble with the police?

This question is very confusing as it is written.

If your husband is in jail your son wouldn't be able to go after him. Have you reported the abuse to the local authorities?

How old is your son?

Lying to the police is a crime and accusing anyone of anything they didn't do, for any reason whatsoever, is about as low as a person can stoop.
We can only guess at what you are trying to ask. Best guess is that your husband hit you, and you are fearful that if you tell your son, he will harm your husband and possibly go to jail for assault or something worse. That could be a legitimate concern because it would definitely make things worse for your family.
Whichever way it is (husband hit you or son hit you), call the police and report it and advise the 911 operator or officer you report it to, that you have concerns about what might happen when the son/husband finds out. This is probably nothing new to police officers who investigate domestic complaints all the time. I am sorry that you are in this situation but you have no choice but to tell the truth and ask for help in the related matter of retribution. Failure to act will only make it worse.