You don't mess with a tooth infection. Those things are nasty and can spread and be serious. I'm battling one now with penicillin. I didn't take it right at first, so I have to do it all over again. I sat on it and didn't mention it and now it's not wanting to go away. So take it as it says and finish the dose. And if it's going to make you sick, it'd would have been in the first 30-40 mins after it breaks down in your stomach. Just take it with food and you'll be ok. They can cause some mild d* after a few days, but that is normal. Get some probiotics to help with that.