Toothpaste has been used for years as a home remedy to help provide relief to single pimples on the face. While this can be a helpful tool, you want to make sure you're using the right kind of toothpaste to prevent negative side effects. Primarily, the toothpaste should be a regular toothpaste without fluoride, as fluoride can actually cause more pimples. You should also avoid toothpaste formulated specifically for whitening teeth. These whitening ingredients can cause irritation and skin discoloration—especially in people with darker skin tones.