Is swallowing the white flakes from the lips or the taste of a tissue after wiping the lips while fasting excusable, and does using moisturizers during the daytime in Ramadan break the fast?

Fasting is easier than you imagine. The fundamental principle regarding acts of worship is their validity, so they are not invalidated by doubt or illusions. The cure for obsessive whispering (waswas) is to completely disregard and turn away from it. Merely licking the lips, feeling their flakes, and wiping them with a tissue during the daytime in Ramadan does not invalidate the fast, nor does it necessitate rinsing the mouth. There is no harm in applying moisturizer or cream to the lips while fasting, as long as the fasting person does not intentionally and knowingly swallow any of it. If they do swallow it, then they must make up that day.