What should i do and what could have happened?!

Today i was at a basketball game cheerin 4 my schools teams, and inbetween 1 of the games we were back stage practicin lows.. I hav done lows like 4 three yrs now and i was doin great until one of my bases dropped me i feel to the left chin first, n my chin started bleeding relle bad, n i scraped my knee 2 but not 2 bad.. I now have a deep medium sized hole on my chin that is still bleeding a little n its been 3 hrs... I also got a relle bad headache and was light headed/ very dizzy.. My chin and knee are both swollen but my chin more.. Ive bleed thru 4 bandaids since this happened.. Wat cud have happened that made me soo dizzy n hav a bad headache, and what shud i put on my chin (wat antibiotics?) thx 4 ur help!