sleep

Hi I need some advice, my son since he turned seven months old has been doing sleep regression. I wanted to know do I start sleep training him now; now he is eight months and three weeks I know with my first son he didn't do sleep regression but I know that I started sleep training him at 10 months of age as advice from my pediatrician but now it seems like my second child everything that's in the books you know as far as the witching hour and such he does so he is doing sleep regression so I don't know if I should do sleep training. It's not that bad he just wakes up maybe every 3 to 4 hours