Crest 3d whitening strips. Contains sodium hydroxide. Hydrogen peroxide. Carbomer. Sodium saccharin. I accidentally swallowed some will this harm me?

No. There is nothing in the way of ingredients that can be harmful to you if swallowed. After all, this product was approved by the fda as safe to use in your mouth and it is expected that some will be swallowed.
Probably not. Ingredients for consumer products usually have a wide margin of safety. While crest strips do work to some degree they do not have the "punch" of professional products--which is why i don't think that swallowing a small amount will hurt you. Just don;t make a habit of it!
You're okay. Swallowing a little won't hurt you. Long term swallowing is a different story. Just like with Fluoride or your toothpaste.
No. Peroxide foams because it gives off oxygen. Spit out excess while bleaching and try not to swallow any if you can.
No . When using the stripsitf makes you salivate more and inevitably some of the medicine will go down your throat but as long as it's in small doses there shouldn't be any kind of issue for you.
Did you..... Swallow the excess whitening solution that remains on your teeth when you remove the strip or an entire whitestrip? Below from website: their website states there is no problem.