well two days ago my bf dropped me off at school then i closed the door and my finger got caught and i did'nt notice i was bleeding untill i saw blood driping on the ground. i ran to the restroom and washed it off. then put on a ban-aid but probem is that it hurts alot.

it bleeded alot and in the night i took off the ban-aid and my thumb was black under the nail. im scared if it can get infected. people tell me to go to the doctors but i dont think it's a big deal? what should i do. it doesnt even let me sleep and sometimes i cry because of the pain.