The fact the dog was shaking it's head and sneezing suggests not only did she hit the dog, she hit it hard enough to cause discomfort and pain. My dogs have bumped their noses off things and have never done this. She's wrong to hit the dog. She's even more wrong to hit the dog hard.
This being said, whilst 1 year is technically a puppy, it's not puppy enough to be getting overexcited at visitors like this, lockdown pup or not. Unless I was well briefed on what training the owner wanted me to take part in for their dog when I arrived, then I'd be asking for the dogs lead, and leading it to another room until it had calmed down. Overexcited dogs jumping around can and frequently do, cause unintended injuries, usually to people. Ever had a broken nose from an exciting dog jumping around but not up?
Your dog is still jumping around not simply because it's a 'puppy', but because you've not managed the behaviour effectively. I love dogs, but I still expect peace from being bombarded by overexcited dogs at friends houses, as they know to expect from me when they visit me. The dogs aren't allowed to greet visitors at all until they're calm. They quickly switch on when they want something (ie - greeting a guest) that the best way to get what they want, is to be calm about, with really very minimal training.
Discipline doesn't equal abuse.
That being said, he likely won't bother her a second time. If you'd disciplined him, she wouldn't have to. And I agree with another poster - an unknown dog jumping up or around me gets a knee put up against it's chest, so it can't scratch me or hurt me. I'm absolutely allowed personal space, and if the owners don't like it, they should train their dogs better. I'm not entering into a wrestling match pushing dogs off me. A) I shouldn't have to, B) It easily encourages it further by 'making it a game'. Turning your back and ignoring a dog doing this is all well and good, until the dog physically hurts you.
Guests absolutely have the right to expect personal space away from animals over-excitedly jumping up or around them when they walk into someones homes. It's basic manners. The dog doesn't know this - but will if you teach it. It doesn't take even the most stubborn dogs that long to learn.