Swallowing drops of water from one's face during salaah

Q: Sometimes I go straight to prayer after I make wudu and some left over water from my face falls into my mouth. I heard that drinking during prayer invalidates prayer. Apparently I did not deliberately drink the water that falls from my face into my mouth and it is almost impossible for me to stop myself from swallowing it along with my saliva once it gets into my mouth. What should I do?

Performing salaah with the urge of relieving oneself

Q: I am taking a class that goes from 5:30 pm to 8:30 pm. Hence it covers asr and maghrib prayers. The class is located far away from where I live. In order to maintain purity (wudhu) for both prayers (there is no cleaning facility at the class location) I used to hold myself not to urine during the entire 3 hour session. Hence for both prayers, especially for the maghrib prayer, I am exerting a huge effort not to let anything come out during the prayer (3 hours are very long). Is my prayer valid?

In addition, even though I tried my best, I cannot guarantee that my pants is 100% clean when I start praying as it is possible that some urine come out while I was in the classroom (that is outside the prayer, before it starts). Does this possible impurity affect my prayer? I almost did my best but I really don't know if my prayers are valid.

Prophetic medicines

Q: I would like to ask you about prophetic medicines, like there are some ahaadith which clearly shows the confirmed results of prophetic medicines as below but sometimes it doesn't work, why? Where is the problem?

Ibn ‘Abbaas (radhiyallahu anhuma) reported that Nabi (sallallahu alaihi wasallam) said: “Healing is to be found in three things: drinking honey, the knife of the cupper, and cauterization of fire.” (Reported by al-Bukhaari, 10/136).

Abu Hurayrah (radhiyallahu anhu) reported that Nabi (sallallahu alaihi wasallam) said: “Whoever is treated with cupping on the seventeenth, nineteenth or twenty first, will be healed from all diseases.” (Reported by Abu Dawood, 3861, and al-Bayhaqi, 9/340. The isnad is hasan).

Al-Bukhaari (5688) and Muslim (2215) narrated from Abu Hurayrah (radhiyallahu anhu) that he heard the Messenger of Allah (sallallahu alaihi wasallam) say concerning the black seed: “In it there is healing for every disease, except as-saam.” Ibn Shihaab said: As-saam is death.

Cleaning dry impurity from the floor

Q: My question is regarding concrete floor and impurity. I know for a fact that some dry impurity fell on the concrete, so I wiped it once with a dry piece of tissue (and should have left it there). But for some reason I had poured water on it and it went underneath the basin of the bathroom. If I tried my best to soak up the water with tissue, would it be considered clean. Keeping in mind I poured water on it once. I was in a hurry because others needed to use the w/c.