there may be a nasal spur I.e. sharp nasal deviation of nasal septum. septal spur alters nasal physiology by changing direction of air currents in to your nose to lungs. mucus is normally circulate in nasal cavity but due to altered physiology it gets dried up. when you try to remove dried mucus or it gets removed itself, it injure mucosa and bleeding occurs. Sometimes moosal layer over nasal spur is very thin, or have a bleeding vessel vulnerable to bleed repeatedly. If you have such kind of spur with problem, it should be removed by septoplasty. you need to instill normal saline nasal drops frequently to moisten nasal mucosa. And have decongestant like xylometazoline nasal drop ( not to be used continuously more than 5 days).