[Disclaimer: I am not a doctor and do not accept responsibility for how this information may be used, misused, or not used. This is what we do that we have found to be helpful. Each reader has to do his own research and seek out whatever help he may need for his health.]
How to Stop a Nosebleed
We tried the "thumbs up method" for stopping a nosebleed a few years ago. It was helpful but we recently tried something else and it works great and stops the bleeding within a few minutes. We take a piece of towel (or whatever is available), roll it up so it is about a half inch in diameter, and put it/stuff it up under the upper lip between the lip and the gums above the front teeth. Push it up high and leave it there (holding a towel over the nose) until the bleeding stops. I think that I read that hospitals may use this technique of putting gauze or something under the upper lip.
[Update: My daughter had an illness and after feeling better she had a massive nosebleed. I think it may have been because her body lacked vitamin C (though I did not know it at the time). I had her start taking vitamin C regularly (maybe 1,000+ milligrams daily) and I don't think that she has had a nosebleed since although she is not taking it so regularly at this time.]