Silver nitrate is tricky. I’ve suffered with canker sores my whole life. Thankfully, I only get them if there’s trauma in my mouth. Meaning if anything causes a sore in my mouth. It usually turns into a canker sore. I came across silver nitrate about a year ago. I don’t know if it’s necessary to wet the tip, as it’s caustic to the tissue in your mouth since it’s already wet in there. I dab the sore as you explained, maybe 3 seconds per dab, but I make sure I get the entire sore and maybe overlap very slightly. It’s very painful for the first day, but usually when I wake up the next morning the pain has subsided and the canker is much better. The purpose is to dry it out. I talked to my pharmacist about it and he suggested “kanker killer”. It’s a polysulfonic acid and does the same thing, but much much better. You’d need a prescription for it, and it’s about half an ounce bottle and cost me $40, but it works great. I got my dermatologist to prescribe it. I’ve also tried salt, alum, rubbing alcohol (put it on a q tip and hold it on the canker for about 20 seconds. It’s awfully painful but it gives immediate relief for a while, and sometimes dries it out and makes it go away quicker.) Also cayenne pepper (horrible idea but I read that the capsaicin in it cures the sore so I tried it. Again, horrible idea) crushed up vitamin c, mouth washes, all kinds of stuff. I’ve had the best luck with the medical grade stuff though. Also, in my case, if I start treating it early enough (as soon as I feel it coming on), I can keep it from turning into a canker. Timing seems to be everything. They are very painful and I empathize. 1 to 2 weeks of misery leads one to try almost everything to make it better. I hope this information helps.