Time, antibiotics. These things generally resolve by themselves with time. They hurt and itch but don't scratch or try to squeeze it. You might try some warm, moist compresses to encourage it to come to a head sooner. Antibiotic ointments (otc) can help. Don't play with it-can spread infection (potentially a very big deal, given the anatomy).
Pimple inside nose. A pimple inside the nose may be a pimple, folliculitis or MRSA (methicillin resistant staph aureus) infection. These will tend to present similarly; a painful bump or area inside the nose. Since the worst of these, mrsa, needs to be treated very specifically to avoid progression to a more serious illness, i would see your doctor for an exam or culture to rule out mrsa.