Why won't my screen work

My iPad had been dropped and started to occasionally not work. There is not visible damage at all, it was in a case. My iPad worked after it was dropped at first but then my screen wouldn't turn on, I could hold my home button down and Siri would respond to me and my music would be playing but my screen won't respond. I reset my iPad to see if it would help. My screen then just started to work when it wanted to. Sometimes it works sometimes I get no response so I would reset it and it would turn back on. Then I got home from school one day and it just wouldn't respond at all my music was playing to I tried to reset it but the apple symbol wouldn't show up, my music stopped playing so I assume it turned off so I tried to turn it on again and it won't, I tried plugging it in still no response, i tried hooking it up to my computer still no response, I try end leaving it plugged in and even unplugged to die then restart and I can't seem to get any response form it at all anymore. I really need to know what's wrong so I can get it fixed I need it for school. Please help me