Ok so I used some hydrogen peroxide (3%) over the counter solution as a mouthwash. I took a mouthfull of water and added just a squirt to it, less than a teaspoon probably. I gargled and swished with it, I did this twice and the second time I swallowed maybe less than a 10th of the mouthful, if I even did at all I really couldn't tell. I drank two other bottles of water quickly after and called poison control and the said as long as I didn't vomit twice or more not to worry.
I am still freaking out as I read the safety sheet and it said that in vitro it can damage DNA