If he didn't hot 1st he would have got hit, my be caught on camera, already got a record from 10 years ago, what will happen

Where? Your question is very difficult to read BUT am I correct - he hit someone to keep that person from hitting him, he has been arrested, what will happen because there is a previous assault charge - ? Is that the question?

Where?

Off probation from previous crime ?

Most likely fines and probation

Hitting first is normally not self defense, thus why they are charged.