Dehydrated dog?

My dog had surgery in the beginning of the week and has been wearing a cone ever since. I've noticed he's smacking and licking his mouth a lot afterwards and I'm worried it might be a sign of dehydration? He always have access to his water bowl obviously, but maybe it's hard for him do drink from it? I've seen him drink from it, but is there any way or type of bowl that makes it easier? I've also offered him water by holding a bowl for him but then he doesn't want it. He had a surgery last summer as well and then I had to give him water through a syringe because he didn't drink enough and it was during a heat wave. Should I start doing that again now or is this a normal thing?