The dog does not hate you.
He is likely in physical pain or traumatized....possibly from a hidden injury during grooming, or because the experience was stressful. Now, your presence is linked in his mind with pain and discomfort, so he is defending himself.
His reactions are not random; dogs always give warning signs like growling, but people often miss them.
For now, stop trying to touch or pet him. Give him space. Take him to a vet to check for any cuts, infections, or pain. Training will not help in this situation. First, address the pain. Then slowly rebuild trust...let him come to you.