My dog got sick and I stayed home do I tell my boss?

Tell your boss you took a personal day and tell them nothing else. This is what personal days are for.

yes, just tell them you are out sick today.

why is none of their business...

Giving too many variables. Here's a couple of questions.

Do you have any sick or vacation days at your job? Do you even live in a country that forces employers to give employees sick days and personal days?

Thanks!

I get paid sick days but I’ve been sick alot I don’t want to mess up

Then takes personal day. Also of importance is what’s going with the dog’s health. Perhaps seeing the veterinarian is in order?

Lying to a boss is a great idea. What could possibly go wrong?

Thanks!

Why the thanks?

She's thanking me for making her reconsider a bad action. Lying to the boss is not good.

You likely already have messed up. Quit taking sick days, unless you're really ill, in which case you should go on short-term disability or be in the hospital.

Employers (all employers, BTW) want reliable employees. Unless you're contagious or near death, go to work (esp. in your case with your extensive sick leaves).

If you're too ill to work, you shouldn't be in that job (unless on approved leave). It's very irritating for employers/bosses to have someone continually calling in sick. It's a hassle to find a replacement (in some cases impossible), and you're letting your team down. Probably none of your team appreciates that as they have your work to do as well as your own.