A hard bump inside the nostril is usually considered to be a nasal vestibule boil, and touching the hard bump will cause painful symptoms. If you touch the hard bump repeatedly, it will stimulate the hard bump to increase in size. This hard bump is mostly caused by repeatedly stimulating the mucous membrane of the nasal cavity by picking the nose with your finger, or it may be caused by bacteria and viruses in nasal snot infecting the mucous membrane of the nasal cavity during a cold. For treatment, you need to wash the area with water and apply erythromycin ointment or mupirocin ointment locally to reduce inflammation and swelling. Twice a day, systemic treatment for one month, usually disappear. If the hard bumps do not disappear after one month of the above medication, surgical removal needs to be considered. It is recommended to forbid touching the bumps with your hands and to eat a light diet without spicy and stimulating food.