Hitting?! How to stop it

I've stopped with the high fives as I think he doesn't understand the difference between hitting a hand vs anywhere else. I find it hard and even tonight have been slapped on the face. My way to tackle it is to stop what we are doing and get free hands, say no hitting, then gave it 30 seconds before resuming what we were doing. I have no idea if it's the right approach, but those steps generally seem to give me and him time to not react more. Would love to know if anyone actually knows how to stop it

My little girlie has just started to lightly slap my face & pull my hair when I pick her up or stop her from doing something. I’ve tried holding her hands, slightly raising my voice, lowering my voice, gentle hands etc. I just keep saying no & holding her hands, hoping it will stop sooner rather than later! It’s so hard x

What works for me is “becoming” sad because it “hurt” me and she goes owww, gives me a hug or kiss and feels bad (I think🤣) she doesn’t do it again in the moment but this is like a weekly thing atm of her not controlling her impulses yet imo . Rarely she might go to hit my nan and that’s when I will raise my voice and she realises quickly she is not to hurt our elderly nana . I try to keep my raised voice for only serious things like hot/sharp/dangerous things so she takes me seriously when it’s a serious matter 😅 it works so far for me. I gentle parent for normal situations but raise my voice for serious things 😅