There is a
personal-hygiene tag, for yourself, but I recently asked a question about other people and there was no
Could we possibly get a hygiene tag?
personal-hygiene should work for anyone's hygiene, not just your own. If it relates to the hygiene of a person (as opposed to any other thing), then it's personal hygiene. If you look at the questions tagged with personal-hygiene, even excluding yours, there are several that relate to other people.
So, I think the use is already what you wish it to be.
I see no need for a second tag at this point.