I got hit in my left ear by slaps and punches! I'm having a slight problem of hearing and when I applied some ear drops in my ears, the drops came running out through my mouth with lots of pain effects. Could you please help me.

See a doctor. You could have a punctured ear drum.

I saw a doctor and he said its 'Ear trauma'... is that dangerous. I'm scared!

Its depends. But yes it can be dangerous. What can happen is if you get too much fluid behind the ear and pressure builds. You can get vertigo. The sensation of spinning without actually spinning. Did you ask your doctor questions? If you were to be driving a car or operating heavy machinery and you get vertigo it will disorient your world. That could be dangerous.