Iphone won't turn on

my iPhone 6s won't turn on it was on lower battery when it died and i looked on you-tube for any help i swabbed my charger the inside of the charger inside of the iPhone plug in but nothing has worked so far it was a bit disgusting inside but it still wouldn't charge i check the charger with my sisters iPad and it did chager so it is my phone that has a problem do you know how to fix it or why did it happen?